Palestinian militants declared on Thursday a halt to attacks on Israel for the rest of this year, their longest ever cease-fire promise and a success for Palestinian leader Mahmoud Abbas (search). But they warned that the truce will collapse if Israel does not hold its own fire and release Palestinian prisoners.

Abbas had been seeking a public commitment from the armed groups Hamas and Islamic Jihad to a long-term cease-fire in order to put pr on Israel to move forward in the peace process — and the step brought praise from Prime Minister Ariel Sharon (search).

Sharon said the announcement was a "positive first step," though he insisted that for greater progress to take place "terrorist organizations cannot continue to exist as armed groups." A top aide to Sharon, Ranaan Gissin, said Israel would continue to refrain from military action as long as Palestinians cease violence against Israelis.

The declaration was agreed to by the 13 main Palestinian factions including Hamas (search) and Jihad after three days of talks in 6th of October City, outside Cairo. It extends a shaky cease-fire that began in early February, and Abbas is hoping that it will prove more durable than ones in the past.

But Hamas and Jihad — the main groups that have waged a campaign of violence against Israel — preserved a broad loophole allowing them to call an end to the cease-fire. The declaration says the halt in violence is conditional on Israel's halting all military operations against Palestinians and releasing all 8,000 Palestinian prisoners, a step Israel has shown no sign of taking.

"What has been agreed upon is that the period of calm will have an upper time limit which is the end of the year," said Mohammed Nazzal, a Hamas leader. "But ending the period of calm will be in our hands, especially if there is no adherence to the conditions."

The term of the deal was somewhat shorter than the full year Abbas had been seeking going into the talks, and the Palestinians avoided the use of the word "cease-fire" or "truce" in their declaration — using instead the weaker term "atmosphere of calm." The final agreement issued by the factions, including Abbas' ruling Fatah party, also underlined that the Palestinians maintain their "right to resistance in order to end the Israeli occupation."

Still, pressure is high on the militants to stick to the full nine-month truce, even if a full prisoner release does not come soon and even if there are military frictions with Israelis on the ground.

Abbas hopes a declaration will fire back up the optimism that filled the peace process after he succeeded the late Yasser Arafat as Palestinian leader. In particular, he believes it will get Israel to carry out its promises to hand over more West Bank towns and carry out prisoner releases — and eventually lead to a return to broader negotiations.

Hamas and Jihad called a cease-fire in early February and violence has dropped dramatically since. Abbas and Sharon held a landmark Feb. 8 summit at the Egyptian resort of Sharm el-Sheik, calling a halt to all violence. The peace was shaken, however, by a deadly Islamic Jihad suicide bombing on Feb. 24 that prompted Israel to freeze its promised handover of West Bank towns and freeing of some prisoners.

The militants' previous promise to halt violence came in June 2003, with a cease-fire due to last three months that instead fell apart after only six weeks.

Abbas "now can go to Israel and to the U.S. and tell them that he has done his homework, and they have to help him in consolidating the truce by more concessions," said Hani Masry, a Palestinian political analyst.

The declaration also comes as Hamas — and to a lesser degree Islamic Jihad — are trying to take a direct role in Palestinian politics, a step Abbas says he hopes will eventually lead them to give up their weapons. Hamas has decided to participate for the first time in upcoming Palestinian legislative elections, and both it and Jihad are seeking a role in the Palestine Liberation Organization.

In the Cairo talks, Fatah, Hamas and the other factions agreed to work out a new election law for the legislative ballot and set up a commission to draw up reforms in the PLO to ensure Hamas and Jihad a hand in decision-making.

"This is a turning point for the region," said Nabil Aburdeina, a top adviser to Abbas. "There is a truce. ... There is a unanimous Palestinian agreement on the Cairo Declaration."

Short of a full prisoner release, the Palestinians may be counting on enough Israeli gestures to keep the cease-fire going. Gissin, the Sharon aide, suggested Thursday Israel could carry out a promised release of 500 more prisoners — which was frozen after the Jihad attacks — if it is satisfied by the Palestinians' steps.

In their final declaration, the Palestinian factions said they agreed on "a program for the year 2005 which centers on continuing the current atmosphere of calm in return for an Israeli commitment to stop all forms of aggression against our land and the Palestinian people and also the freeing of all prisoners."

The term "atmosphere of calm" — in Arabic, "manakh al-tahdi'a" — was used instead of the term "truce" — which the armed groups apparently view as more binding and long-term. The term in Arabic, "hudna," is steeped in Islamic history and means a truce of a fixed duration, usually between Muslims and non-Muslims. Israeli skeptics have said in the past that even the term hudna implies the Muslim side can break it off at any time, a claim denied by Palestinian scholars.

Hamas called the June 2003 truce a "hudna."

Abbas' allies appeared eager to ensure that the new cease-fire would endure.
If there are incidents of Israeli violence, "there won't be a response on an individual basis" by Palestninians, said Sakher Bseiso, a Fatah delegate. "We will get together and consider the next step ... There will be many steps before it comes to getting thrown back into the cycle of violence and counter-violence."