Palestinian militant groups announced a de facto truce on Thursday that would expire at the end of this year if their demands, including military withdrawals and prisoner releases, were not met.
Thirteen Palestinian factions, including Hamas and Islamic Jihad, issued a statement after meeting in Egypt, saying they had agreed to the conditional truce.
Ariel Sharon, the Israeli prime minister, called the arrangement a "positive step" but added that further progress in the peace process hinged on disarming the militants. "The terrorist organisations cannot continue to exist as armed groups and certainly not as terrorist organisations," Mr Sharon told President Hosni Mubarak of Egypt, according to a spokesman.
A ceasefire concluded last month by Mr Sharon and Mahmoud Abass, the Palestinian president, failed to include radical militant groups and the shaky quiet was broken by a suicide bomber who killed five Israelis.
The militants' statement used the Arabic term for calm, rather than those meaning "truce" or "ceasefire", and said it was also dependent on Israel putting an end to the expansion of Jewish settlements in the occupied territories and the construction of the West Bank barrier.
"What was agreed upon today is calm until the end of this year as a maximum period of time in exchange for an Israeli commitment to withdrawal from cities and release prisoners," said Mohammad Nazzal, a Hamas official.
Israel has maintained its stance that any progress towards easing conditions on the ground for the Palestinians depends on a halt to violence. Mr Sharon is concentrating on his plans to withdraw from the Gaza Strip and four West Bank settlements later this year.
"The ball is now in Israel's court. From our side we have a commitment to a ceasefire," said Jibril Rajoub, an aide to Mr Abbas. "The declaration will pave the way to restoring the political process." Israel has charged Mordechai Vanunu, the nuclear whistle-blower, with violating the terms of his release from prison by talking to reporters and trying to visit the West Bank.
He was released from jail last April after serving an 18-year sentence for revealing Israel's atomic weapons programme to a British newspaper.