JERUSALEM - Prime Minister Ehud Olmert dismissed Israel's top negotiator in Gaza truce talks for publicly criticizing his demand that Palestinian militants hand over a captured Israeli soldier before any deal is clinched, officials said Monday.

The move threatens to roil the talks just weeks before Olmert is succeeded by the hawkish Benjamin Netanyahu, who wants Gaza's Hamas rulers toppled and likely would take a tougher line in the Egyptian-brokered truce negotiations.

A truce deal has implications beyond cementing the informal Jan. 18 cease-fire that ended Israel's war on Hamas. Without it, there is little chance of advancing already troubled talks to reconcile feuding Palestinian factions.

Olmert abruptly announced last week that Israel would not reopen Gaza's long-blockaded borders -- the main Israeli concession sought by Hamas -- unless Hamas-affiliated militants first freed Sgt. Gilad Schalit, who was seized in a June 2006 cross-border raid.

Amos Gilad, the fired negotiator, opposed linking the truce deal with Schalit and criticized Olmert's strategy in an interview last week with the Israeli newspaper Maariv. After Gilad refused to apologize, Olmert gave him the boot, aides said Monday.

"Due to the inappropriate public criticism leveled by Mr. Gilad, he cannot continue as the prime minister's envoy to any political negotiations," Olmert's office said in a statement.

Aides said the talks would not be affected. A longtime adviser to Olmert, Shalom Turgeman, will replace Gilad in the truce talks, while veteran negotiator Ofer Dekel will handle efforts to free Schalit, the aides said, speaking on condition of anonymity because of the sensitivity of the talks.

There was no immediate reaction from Gilad or Egypt.

Hamas shrugged off the development, with spokesman Fawzi Barhoum saying Israel "never intended to reach any agreement or closure on a truce or a prisoner exchange."

Hamas desperately wants Israel and Egypt to reopen Gaza's borders, which were sealed after the Islamic group's fighters violently seized control of the territory nearly two years ago. But it has rejected any linkage between a prisoner release and the truce negotiations.

In related news, Al-Qaida's No. 2 leader warned Palestinians in Gaza against accepting a truce with Israel in an audio message posted on extremist Web sites, an Internet monitoring service said.

Osama Bin Laden's deputy, the Egyptian-born Ayman Al-Zawahri, described the truce negotiations as "plots and conspiracies" to defeat the Palestinians after Israel's "aircraft and artillery" failed, according to a transcript provided by the U.S.-based SITE Intelligence Group.

Bin Laden issued his own audio message on Gaza last month, urging Muslims to launch a holy war against Israel. Al-Qaida holds little influence among Palestinians, but its Gaza-related postings are likely meant to harness Muslim anger elsewhere over the Israeli offensive.

The Israeli military launched the three-week assault on Hamas after years of Gaza militants firing rockets into southern Israel.

The sides declared separate cease-fires Jan. 18, but sporadic violence has persisted. Two rockets struck Israel on Monday and an Israeli aircraft fired missiles at a vehicle belonging to militants preparing an assault, the military said. No injuries were reported in any of the incidents.

A truce deal is key not only to Gaza's fate but also to any chance for a power-sharing agreement between Hamas and the Fatah movement of moderate Palestinian President Mahmoud Abbas, who controls only the West Bank after his forces were routed in Gaza.

Efforts to form a unity government have failed in the past, but Israel's Gaza offensive gave both sides greater incentive to try to join forces.

Hamas can't end its international isolation unless it allows Abbas a foothold in Gaza. Abbas has overstayed his term as president, which ended in January, and needs a partnership with Hamas to shore up his dwindling political legitimacy.

For all that, a news conference at the Hamas-run Interior Ministry in Gaza on Monday did not bode well for reconciliation talks scheduled to begin in Egypt later this week.

Hamas officials played videotapes of what they said were Fatah loyalists confessing to relaying information to Abbas' government about weapons warehouses, smuggling tunnels and the homes of Gaza political leaders.

One of the loyalists said he thought the information was later transmitted to the Israeli military and used to locate targets hit during the war. But he provided no evidence to back that claim.