Israel has begun to free more than 400 Palestinian prisoners, a move aimed at giving a boost to the Palestinian Authority as the two sides resume negotiations.
The first bus with the prisoners left the Ketziot prison in southern Israel early on Monday morning, reporters on the scene said.
"Today we are releasing 429 prisoners," Yaron Zamir, a spokesman for the Israeli prison authority, told the AFP news agency.
He said 20 of the freed detainees would return to their homes in the Hamas-run Gaza Strip, with the rest going to the occupied West Bank.
Launching the first formal peace talks in seven years at the Middle East conference in the American city of Annapolis last week, Olmert and Mahmoud Abbas, the Palestinian president, agreed to try to reach a deal on creating a Palestinian state by the end of next year.
Weakened leader
But the Israeli prime minister, weakened by scandals and political setbacks, told his cabinet on Sunday that he would not be bound by the Annapolis deadline.
"We will make an effort to hold speedy negotiations in the hope we may conclude by the end of 2008, but certainly there is no commitment for a firm timetable for their completion," Olmert said.
In an apparent hint to coalition partners that he was not planning concessions without a reciprocal move from the Palestinians, he said any progress on peace would depend on adhering to commitments under a stalled US peace "road map".
Olmert said: "The most important thing in the joint statement is that ... any agreement that we reach in the future will be dependent on completion of all road map commitments.
"In other words, Israel will not have to implement any commitment which emanates from the agreement before all the road map commitments have been met".
Resolution dropped
Olmert's comments came after the US withdrew a draft UN resolution endorsing action agreed to at Annapolis.
Although Israel apparently had no problems with the uncontroversial text, it said a resolution was inappropriate.
Analysts have suggested it was worried a formal resolution would get the UN too involved in Middle East conflict resolution efforts.
The 2003 US road map provides benchmarks that include a freeze of Jewish settlement activity in the West Bank, occupied by Israel since the 1967 Middle East war, as well as a Palestinian crackdown on armed groups.
Both sides accuse the other of not meeting those benchmarks.
Gaza violence
On the ground, meanwhile, sporadic clashes continue. Israeli artillery fire killed one Palestinian fighter and wounded five others in the Gaza Strip on Sunday, Hamas said.
Hours earlier, three Israeli soldiers were injured by mortar fire.
The Israeli military confirmed that it had fired on "suspicious silhouettes approaching the security barrier" and that three of its soldiers "were lightly wounded ... by a mortar round fired from the Gaza Strip".
Israel regularly launches raids into Gaza and said on Sunday it had stepped up attacks in the coastal strip in the past week.
A statement said Ehud Barak, the defence minister, had told ministers he had authorised more military action in Gaza, including the targeting of "manned military Hamas targets".
Punitive steps
Barak said Israel had killed Palestinian 22 fighters in the past week.
Israel also reduced the amount of fuel allowed into the coastal strip last month.
The move has left most Gaza petrol stations closed and brought traffic almost to a halt.
Mahmoud al-Khuzundar, the chairman of the society of petrol company owners, said on Sunday that "cooking gas will run out within days and cars will stop within hours".
PHOTO CAPTION
Palestinian boys march during a demonstration calling for the release of Palestinian prisoners from Israeli jails. [AP]
Al-Jazeera