Israel's prime minister pledged to free more than 150 Palestinian prisoners in a meeting Wednesday with President Mahmoud Abbas, a gesture meant to energize their sluggish peace talks.

The release could also boost the prestige of the embattled Palestinian leader, whose Fatah movement is engaged in a tense power struggle with the militant Islamic Hamas.

The meeting at Prime Minister Ehud Olmert's official Jerusalem residence was the first since the Israeli premier announced last week that he would resign next month because of corruption investigations against him. Palestinians have been seeking assurances that peace talks, started with great fanfare at a U.S.-sponsored conference last November, would continue despite Israel's political turmoil.

Olmert says he is determined to press ahead with peace efforts as long as he is in office. Because of Israel's complicated political system, his term could extend into next year.

The Olmert-Abbas summit came on the day Israel freed five Palestinian prisoners as part of its exchange with Hezbollah guerrillas to bring back the bodies of two soldiers captured in 2006.

With Hamas demanding freedom for several hundred prisoners in exchange for Sgt. Gilad Schalit, an Israeli soldier also captured in 2006, Abbas needs to show his people that he can win freedom for prisoners in Israeli jails by peaceful means, as opposed to the militants' tactics of attacks and abductions.

However, the modest numbers Abbas achieved were not likely to prompt celebration among Palestinians or reduce Hamas' influence. Palestinian negotiator Saeb Erekat said that on Aug. 25, "more than 150" prisoners would be freed, out of about 11,000 held by Israel.

Israeli government spokesman Mark Regev said prisoners would be released this month "as a confidence-building measure, as a gesture of good will."

But it was seen highly unlikely that Olmert would agree to a key Abbas demand: freedom for Marwan Barghouti, the highest Fatah official in Israeli custody, who is serving multiple life terms for involvement in deadly attacks on Israelis. Israeli officials said only that Olmert did not commit to specific names.

Barghouti is also said to be on the list of prisoners Hamas wants released in exchange for the soldier it is holding, but Israel is unlikely to give that kind of boost to the Islamic militants, who do not recognize Israel and have sent dozens of suicide bombings to attack Israelis.

Over the past week, tensions have flared again between Hamas and Abbas' Fatah, starting with a bombing in Gaza that killed five Hamas militants and a girl. Hamas reacted with mass arrests of Fatah loyalists and Fatah hit back with arrests in the West Bank. Then over the weekend, Hamas launched an assault on a Fatah stronghold in Gaza City, an operation that ended with 11 dead, dozens wounded and about 90 Fatah fugitives fleeing Gaza for the West Bank.

On Tuesday a Hamas official hinted darkly of a Hamas uprising similar to its sweep through Gaza last year, when it expelled Fatah forces and took over the territory.

After nightfall Palestinians fired a rocket at Israel from Gaza, the military said, in violation of a June 18 cease-fire. It exploded harmlessly in a field.

Israel is trying to stay out of the internal Palestinian conflict, but it is negotiating with Abbas while boycotting Hamas as a terror group.

Some Israelis have hinted that Barghouti, who had broad contacts with Israeli doves, might be freed someday — but probably in the context of significant progress toward a peace accord. Israel's official position is that Palestinians convicted in fatal attacks cannot be freed.

However, it has made exceptions, most recently three weeks ago when it released Lebanese prisoner Samir Kantar as part of the Hezbollah deal. Kantar was convicted of the 1979 killing an Israeli father, his daughter and a policeman.

Erekat said Abbas asked for release of imprisoned politicians, including Barghouti, as well as hundreds who have served more than 20 years in prison, women and minors. But Erekat said the criteria were not agreed on at the meeting.