RAMALLAH, West Bank - Palestinian President Mahmoud Abbas said Thursday he hopes to reach a peace deal with Israel within a year, after reportedly receiving a promise from President Bush to push hard to conclude a Mideast agreement before the end of his term in 2008.

Israeli Prime Minister Ehud Olmert wants to start by formulating a "declaration of principles" with Abbas on the contours of a Palestinian state in Gaza and most of the West Bank, Olmert's aides said, confirming a report in the Israeli daily Haaretz.

However, such a declaration would likely sidestep the most explosive issues, such as final borders, an arrangement for Jerusalem and the fate of Palestinian refugees.

In Gaza, meanwhile, Israeli airstrikes killed four Palestinian militants, including the top military commander of the Islamic Jihad group in Gaza, Omar Khatib.

One missile attack killed Khatib and two other Islamic Jihad members traveling in a car south of Gaza City. After the attack, other Islamic Jihad activists tried to retrieve items from the car but were stopped by members of the Hamas security forces, according to witnesses.

A firefight erupted, and four Islamic Jihad members suffered gunshot wounds, according to the group, witnesses and officials at nearby Deir El Balah hospital where they were treated. Hamas officials had no immediate comment.

Also Thursday, a leader of Abbas' vanquished forces in Gaza, Mohammed Dahlan, said he would resign as national security adviser, citing health reasons. Dahlan was widely blamed for the surprising collapse of the pro-Abbas forces in five days of fighting that ended with Hamas' takeover of the coastal strip.

Abbas has already dismissed more than a dozen security commanders following the fall of Gaza.

The Hamas takeover of Gaza has spurred a flurry of diplomatic activity, with the international community lining up behind Abbas and a West Bank-based government of moderates he has installed. The backlash against Hamas has also given new momentum to efforts to reach a final peace deal.

Bush has said an international peace conference would be held in the fall, Secretary of State Condoleezza Rice is arriving next week for more talks with the Israeli and Palestinian leaders, and former British Prime Minister Tony Blair is settling in as the international Mideast envoy.

Abbas was quoted Thursday by the Israeli daily Maariv -- and the comments were later confirmed by his aides -- that Bush and Rice told him they'd push hard for a final peace deal within a year.

"The Americans are determined to push the sides to reach a peace agreement during President Bush's current term," Abbas was quoted as saying.

"I heard this with my own ears from the president himself and from Secretary of State Rice," he told the paper. "They want to reach an agreement between Israel and the Palestinians in the next year."

Asked Thursday about the U.S. assurances, Abbas was evasive, but told reporters at his headquarters: "We hope to have a comprehensive peace with the Israelis within a year or even less than that."

Abbas also appeared to be welcoming Olmert's idea of a declaration of principles. He said statements by Israeli officials and a report in the Israeli daily Haaretz on Wednesday -- the day the newspaper wrote about Olmert's plan -- were "encouraging." Abbas said the idea has not been formally raised by Israel yet.

In the Maariv interview, Abbas said his recent conversations with Olmert were wide-ranging. "We talked about everything, including a diplomatic horizon. I'm optimistic," he said.

Concerning a peace deal, he said: "We have to arrive at the final formula, the 'end game,' and then think about implementation and set a timetable for implementation on the ground."

"It's likely that implementation will take time, that the timetable will be drawn out, but what's important is that the Palestinians know the final result, the endgame, at the start," he was quoted as saying.