Israeli airstrikes in the Gaza Strip left four Palestinian militants Thursday as Palestinian President Mahmoud Abbas said he hopes to reach a peace deal with Israel within a year.

Abbas made the announcement 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, an official committee of inquiry concluded that sixty members of Abbas' security forces in Gaza should be court-martialed for their failure to prevent a Hamas takeover there last month.

The final report is to be made public Friday.

Earlier Thursday, Mohammed Dahlan, a leader of Abbas' vanquished forces in Gaza, announced that he is resigning as national security adviser. Dahlan cited health reasons, but Palestinian government officials said Abbas asked him to step down because the committee of inquiry concluded Dahlan bore much of the responsibility for the humiliating defeat of the pro-Abbas forces by Hamas in mid-June.

Dahlan's office denied he was asked to resign, and said he stepped down for medical reasons only.

It was not clear whether Dahlan is among the 60 officers to face trial in a military court.

The committee was headed by a senior Abbas aide, Tayeb Abdel Rahim. Investigators heard 120 hours of testimony, including from Dahlan and other senior security commanders.

The official in Abbas' office said the investigation found flaws in the performance of Abbas' troops, but did not elaborate. He spoke on condition of anonymity because the report has not yet been published.

Among the 60 facing trial in a military court are officers of various ranks, he said.

Abbas has already dismissed or accepted the resignation of more than a dozen Gaza security officers.

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.