On the television screen a woman is reading slowly from a sheet of paper held close to her face. The moment is awkward. Her hands shake, she avoids the camera and a large, black M-16 assault rifle hangs from her shoulders. Her head and neck are wrapped tightly in a white scarf.

This is the final message in the life of Fatma al-Najar, widow, great-grandmother, matriarch of her large family and, a few hours after this brief video was shot, the oldest Palestinian to become a suicide bomber. "I am the living martyr Fatma al-Najar," she says, and praises the armed wing of her beloved Hamas movement, its political rulers and its violent struggle.

She says a few words to her family. "I ask my sons to go to the mosque and keep up their prayers and my daughters to survive and not to cry, and to give out sweets." The film stops and restarts and now she is standing without the paper, looking into the camera, behind her still the green flags and insignia of Hamas. An unseen figure prompts her to speak. "I don't know what else to say," she says, smiling nervously. The film is cut.

A few hours later, the 70-year-old arrived at the Jabaliya refugee camp, not far from her home in the northern Gaza strip, in the final days of a major Israeli military incursion. She walked towards a group of soldiers. They called her to stop a little way off. One soldier, thinking she looked suspicious, threw a stun grenade. She detonated the belt of explosives around her waist, tearing her body to pieces and slightly injuring three soldiers.

There have been a handful of women among the 120 Palestinian suicide bombers of recent years, and their names are recited on the streets of Gaza in the folklore of Palestinian martyrdom. But the past few weeks have seen a remarkable injection of women's activism into the fight. In this conservative and patriarchal society the militancy has previously been almost entirely dominated by men. Now that is changing.

Three weeks before the al-Najar bombing, hundreds of women, mostly Hamas supporters and all clad in long cloaks and headscarves, marched into the town of Beit Hanoun in the middle of an Israeli incursion to free a group of armed male fighters who were holed up inside a mosque. Two of the women were killed, but the crowd succeeded in freeing the fighters and now boast proudly of their bravery.

A few days later, another woman from Gaza, Mirvat Masoud, an 18-year-old university student, blew herself up near a group of Israeli soldiers, again in Beit Hanoun. In the following days, crowds of men and women staged sit-ins at the homes of several militants whose houses, the Israeli military had warned, were about to be destroyed. The Israelis had to call off their air strikes.

As with the men, the women's actions are seen publicly as statements of defiance. And among the first guests at the three days of mourning at the al-Najar household, held under a green woven tent in a courtyard by their bare concrete houses, was Ismail Haniyeh, the Hamas prime minister, and others from his government. The movement paid the funeral costs and Khaled Meshaal, the all-powerful, exiled head of the movement's political bureau, telephoned the family to tell of the great blow their mother had struck for Hamas.

But the family she has left behind feels less proud than shattered. They struggle to explain what has happened. Al-Najar had seven sons and two daughters. All had children, some had grandchildren. There were around 80 in the family, all living within a few narrow streets of each other, all deferring to her as the head of the household. Several of the sons were jailed, one for nine years, during the first intifada, the Palestinian uprising that began in 1987. The family house, in Jabaliya town, was destroyed in an Israeli airstrike and rebuilt. Then, in the middle of the second intifada, in 2002, her grandson, Adil, aged 18, was killed battling Israeli troops in Gaza. The household is still politically divided. Some of the sons are Fatah supporters and at least one works for Force 17, the Fatah security service. Others, like al-Najar herself, are Hamas activists.

Fathiya, 52, the eldest daughter, last saw her mother mid-morning on the day of the bombing. She came to the house and found her mother making bread. They sat and talked for 20 minutes. Fathiya made as if to leave, but her mother asked her to stay for lunch. Her mother showered and changed and walked to the local market, where she bought clothes for her grandchildren and boxes of sweets. She returned home and a few minutes later, left again. None of the family, it appears, suspected what was on her mind. "When she left she said goodbye, but she asked us to wait for her," says Fathiya. Her mother did not return. Later, at sunset, the mosques began announcing there had been a suicide bombing. Soon they broadcast her mother's name. Later, an ambulance crew collected the remains of her body and buried it under a mound of soft sand in the local graveyard.

"Some people say she must have been depressed," says Fathiya. "But it wasn't true, she was a religious woman. She did this to fight the Israelis and get them out of our land. She blew herself up because she loved her home, she loved paradise and she loved the mujahideen."

Her brother, Samir, 36, the Force 17 soldier, seems less attached to the rhetoric. "Now we are missing a space in our lives. We have only our memories, every moment, every second." He knew his mother had become increasingly politicised, but is surprised at her radicalism. She had, he thinks, been affected by the fighting of recent years, the growing poverty in Gaza, the failures of the long-stalled peace process. "She was changing. She watched the news all the time," he says. "It began to affect her. She started going to marches and funerals." She also started to help support the armed wing of Hamas, though she did not tell her family.

In the middle of November, al-Najar and Fathiya took part in the women's march into Beit Hanoun, one last radical act before the bombing. The sons were worried and spent the day at home waiting for her to return. Fathiya saw no reason for their anxiety. "It was something normal. We went to protect our mujahideen. We have to be shields to protect our men."

One of the organisers of the march was Jamila Shanti, 50, a leading woman within the Hamas movement, a member of the Palestinian parliament and a professor of philosophy at the Islamic University in Gaza. She headed the list of Hamas women candidates in the January elections, when women were crucial in getting out the vote for the movement and propelling it into a position of power for the first time. A single, educated women committed to the most radical of Hamas political positions advocating the destruction of Israel, she is a powerful force in the movement.

When Israeli forces occupied Beit Hanoun, Shanti encouraged her women supporters to play an active role in the fight by marching into the city, past Israeli tanks. Some of the women reached the Nasr mosque, where the fighters were sheltering, and helped them leave despite the Israeli military presence all around.

"It was a great success because we freed so many fighters," she says. "We did something our authorities couldn't do. We sent a message to the world." Then Shanti helped organise the sit-ins to defend Hamas houses against Israeli air strikes. It was another role for women in the fight. "As Palestinian women, we feel strong enough to do anything, strong enough to play a great part in our conflict," she says.

The battle of Beit Hanoun was one incursion in a five-month Israeli operation in Gaza that followed the capture of an Israeli corporal in June. The soldier has still not been freed, although a tentative ceasefire began last week that might yet bring his release. The five months of fighting left more than 375 Palestinians and five Israelis dead and left many feeling that a return to serious peace negotiations was further away than ever.

Among the dead was Shanti's sister-in-law, who was killed near her home in an Israeli strike that also killed a Hamas fighter. Days later, Israeli troops rolled up in a tank outside Shanti's house and stormed the building, apparently intent on arresting her. She was away at the time.

Others who went on the Beit Hanoun march came away, despite the risks they faced, with the same sense of assertion. "It was a way of encouraging women to do something. We did something that the Arab leaders couldn't do," says Um Ahmed Kafarna, 40, a Hamas activist and the wife of Beit Hanoun's Hamas mayor. "I think more women will be encouraged to be suicide bombers and leaders and politicians."

Academics point out that Palestinian women have been involved in fighting for many decades, even during the British mandate before the creation of Israel. For a long time the leading Islamist groups, Hamas in particular, refused to send off women as suicide bombers, saying it was a role reserved for men, says Islah Jad, assistant professor of gender studies at Birzeit University, in the West Bank. That began to change about three years ago. What is most striking now are events like the Beit Hanoun march, says Jad.

"To use this collective power of the people is something very new in the political scene here," she says. "Before, the women were glorifying martyrs and martyrdom; now, they speak about their power themselves as women." It was the women within Hamas, partly by design, partly by trial and error, who have begun to push beyond the group's vague assertions of its support for women to seize a much bigger, more practical role.

But although the voice of militancy is often the most powerful in Palestinian society, it is by no means the future everybody sees. There are many who consider the past six years of fighting as a great setback and who argue for negotiations, not war. Others are caught in the middle.

In the town of Beit Lahiya, only a few minutes' drive from Beit Hanoun, is a small, private kindergarten. On Monday November 6, at around 7am, the school minibus was collecting the children for class. It stopped in the Sheikh Zayed neighbourhood to wait for one boy. At that moment an Israeli shell struck nearby and a splinter of shrapnel flew into the minibus and into the neck of Najwa Khalif, 24, a teacher who was sitting in a middle row with her two children, Manar, five, and Wasim, three. She died several days later in hospital. The Israeli military said it had been targeting militants nearby who had launched rockets into Israel the previous night. The teachers say they saw no fighters on the school run that morning.

The children on the bus have been deeply traumatised. The head teacher, Indira Gandhi Hamuda (her father was an admirer of the late Indian prime minister), has had them draw sketches of the attack to help them recover. The crayon pictures show images of the bus, hospital stretchers, a rocket, an Israeli tank and, on almost every one, scribbles of red blood stretching over the page. "This is the occupation. They make no difference between children and fighters," says Hamuda, who, like most women in Gaza, dresses in a conservative headscarf and long cloak.

She is bitterly angry about what has happened, but says she is opposed to women taking up suicide bombing. "I don't support this at all. It is also a jihad to care about your children and to bring them up well," she says. And, after all, she adds, the bombing had hardly achieved a major military objective. "What did it do? It was just a suicide. If I'm facing a tank, there isn't anything I can do," she says. "Women can do something else, like teach their sons and daughters to become doctors and engineers. We don't all need to be martyrs."

While she is watching over a class, two of her younger teaching assistants are in the school office, staring attentively at a computer. They call up the news footage from al-Jazeera about the death of the teacher, gasping when they see her body carried away on a stretcher. Then one calls up a video recorded by another female suicide bomber, Mirvat Masoud, the 18-year-old university student who blew herself up in Beit Hanoun on the same day as the bus attack.

"She's not just anyone. She's a martyr," says Iman, 22, one of the assistants, as they watch the film. "We all want to be like her. I would like to be a bomber, but my family won't allow me."

"I want to go instead of her," says the other assistant, Randa, 23, who was on the bus the day their fellow teacher was hit.

If Fatma al-Najar was the oldest suicide bomber, Mirvat Masoud was one of the youngest. She was in her first year at the Islamic University, studying science. She was the eldest child and already the most religious in the family. When she was growing up, the politics in the household was Fatah, the more moderate of the Palestinian factions. When she went to the Islamic University, one of the best in the Gaza strip, there was no Fatah student movement and she fell in with a group from Islamic Jihad, one of the radical movements.

"When she told me that she had joined, I thought it was just politics," says her father, Amin Masoud, 40. He was protective, refusing to let his daughter join the Beit Hanoun women's march. He shows off her school report cards - most years she was top of the class.

The family live in a UN refugee house, provided because the grandparents fled Israel in 1948. Mirvat woke early on the morning of the bombing, ate a little breakfast with her mother, and went off to university. That afternoon, the family saw on the television news that there had been a suicide bombing in Beit Hanoun. One Israeli soldier had been slightly injured. Soon a man from Islamic Jihad arrived to tell them their daughter was dead.

"We don't expect to send our sons and daughters to die. But when they watch the television news, the killing and the destruction, they are affected by it," says Mirvat's father, Amin. "It creates a deep hatred inside them."

In the video that she made before her death, there are slight, dark rings under the teenager's eyes but she is confident and stares intently into the camera. She is dressed in a headscarf and black baseball cap marked with religious script and a conservative but fashionable patterned cloak. She holds a rifle upright in her right hand and addresses her family. "This multi-coloured life comes to an end," she says to camera. "My mother, please live on and pray God to forgive me. We willmeet in paradise. My father, please forgive me if I did anything wrong to you. My uncles and aunts, this is very hard for me, I miss you." She praises other Islamic fighters across the world, "from Iraq to Chechnya, from Palestine to the Philippines". She asks her family to pray, and notes that they should distribute sweets but not coffee at her funeral. Then she says: "I am the living martyr, God willing, Mirvat Masoud". Although the Palestinian history of the conflict with Israel has long been dominated by men, there have been several high-profile women figures, often fighters and activists, and occasionally politicians and leaders.

The woman regarded as the first female Palestinian guerrilla fighter is Fatima Barnawi, who in October 1967 planted a bomb in a Jerusalem cinema that left dozens of Israelis injured. She was 28 and a member of Yasser Arafat's Fatah movement.

Perhaps the most iconic Palestinian woman was the hijacker Leila Khaled. In 1969, she took part in the hijacking of a TWA plane, flying it to Damascus before blowing it up. She had cosmetic surgery to disguise her looks and the next year made a failed attempt to hijack another plane as part of a wave of hijacks planned by the leftwing Popular Front for the Liberation of Palestine.

Nearly a decade later, Dalal Mughrabi landed with a group of other Palestinian fighters on an Israeli beach, killed an American photographer and seized a bus filled with passengers. After a gunbattle with Israeli soldiers, she blew up the bus, killing 36 people on board. Mughrabi and her fighters were also killed.

Other women became prominent without violence. Hanan Ashrawi, an academic and a Christian, emerged as one of the most articulate voices for the Palestinians. She became a government minister and today holds a seat in the Palestinian parliament. The most high-profile Palestinian woman today is probably Queen Rania of Jordan, who was born in Kuwait to Palestinian parents and has become an important supporter of charities.

Today, a new generation of women are taking part. Wafa Idris, a divorced paramedic, became the first Palestinian female suicide bomber in January 2002 when she detonated a bomb in Jerusalem, killing an elderly Israeli man. Female militants and politicians are now emerging from the Islamist groups, notably Maryam Farhat, known as Umm Nidal, who was elected a Hamas MP this year after three of her sons became suicide bombers.