Mariam Farhat, an icon of the intifada, will join male Hamas leaders to contest a legislative election due in January in which Hamas, the Islamist group sworn to Israel's destruction, is taking part for the first time. It is expected to present a serious challenge to Fatah, the party of Mahmoud Abbas, the Palestinian president.

Farhat, 56, has strong militant credentials, including an appearance carrying a gun in a video in which she advised one of her sons, Mohammed, on tactics before he attacked a Jewish settlement.

Mohammed, 17, killed five Israelis before he was shot dead in the assault in the occupied Gaza Strip in 2002.

Farhat's eldest son, Nidal, was killed in 2003 as he was preparing for another attack. A third son, Rawad, died earlier this year in an Israeli air strike on his car, which was carrying rockets. Three other sons are still alive.

Farhat, popularly known as Umm Nidal and regarded by Palestinians as a "mother of martyrs", said: "I am pleased that Hamas trusted me and I declare I will be at the service of my movement."

Hamas's choice of Farhat, seen by Palestinian analysts as a sure vote-winner, appeared to demonstrate just how serious the group is about its challenge to Fatah's traditional dominance.

In addition to senior leaders, some in Israeli jails, university professors and engineers, Hamas also plans to back several independents and at least one Christian. It hopes to establish a bloc of lawmakers that could prevent progress towards peace with Israel.

Israel and the US are concerned that Hamas, which has built up a social welfare network in the occupied West Bank and in the Gaza Strip, could do well in the election, seen as a test of the leadership of President Abbas.

However, Abbas, a moderate, has rejected Israeli calls to bar Hamas from the vote, while struggling to salvage Fatah's image after party primaries that were tainted by violence and allegations of fraud.

Farhat said the decision of Hamas to participate in mainstream Palestinian politics did not contradict its military goals.

"The jihadist project completes the political one and the political project cannot be completed without jihad," she told Reuters, using the Arabic term for "holy struggle" against the Jewish state.