WASHINGTON — Despite looming criminal indictments at home, Israel’s embattled prime minister is pressing forward in pursuit of peace deals with Syria, the Palestinian Arabs, and possibly even Saudi Arabia.

In remarks yesterday evening at the annual American Israel Public Affairs Committee policy conference here, Prime Minister Olmert told an audience that included more than half of the American Congress that he thought his negotiations with Syria could yield a “drastic, strategic shift in the entire Middle East.” While pledging never to compromise Israel’s “security or vital interests,” Mr. Olmert also said an Israeli détente with Syria could further weaken and isolate Iran.

On his negotiations with the president of the Palestinian Authority, Mahmoud Abbas, Mr. Olmert said he hoped “the moderate, responsible Arab states, headed by Saudi Arabia and other Gulf states, could play an important role in this process.” He also stressed that a peace deal was possible by the end of 2008, the same time line President Bush has placed on the process, which began in November in Annapolis, Md.

Secretary of State Rice, in her remarks to Aipac earlier yesterday, gave a more cautious reading of the peace process, saying the work should continue with whomever succeeds President Bush in the White House.

While Mr. Olmert yesterday held out an olive branch to many of Israel’s neighbors, he drew the line at talks with the Iranian-funded group that controls Gaza, the territory Mr. Olmert’s predecessor relinquished in 2005.

“Israel has never, nor will it ever, negotiate with Hamas, as long as it refuses to accept the three principles set forth by the international community,” he said.

Mr. Olmert later said Israel would not be deterred from launching a “large military operation in Gaza if and when we come to the conclusion that this is the best way to restore calm on our southern border.”

So far, Israel has resisted a reinvasion of the territory, opting instead for targeted air strikes against Hamas leaders. “Every day, the government and the security forces weigh all possible alternatives, and make the choice which we believe is the wisest and most effective,” he said.

Mr. Olmert’s push for regional peace comes amid a criminal probe of his activities at home. Last week, a Long Island businessman, Morris Talansky, testified publicly that he gave Mr. Olmert $150,000 in cash for party building activities. The scandal has prompted his foreign minister, Tzipi Livni, to call for his resignation. Mr. Olmert has said he would step down if indicted.

At the end of his speech yesterday, Mr. Olmert made reference to the scandal. “Given the recent political developments in Israel, of which I am sure you are all aware, I hesitated as to whether it was the right time and the right thing to leave everything behind and meet with you today,” he said. “I didn’t hesitate for too long.”

“Israeli politics is accustomed to all kinds of trials and tribulations, but your love and support for the state of Israel provides a powerful foundation, a solid rock on which we know we can always rely, in good times and in times of crisis,” he told the crowd.

Mr. Olmert is scheduled to meet with Mr. Bush and Vice President Cheney today. The prime minister’s staff has explored possible meetings with the Republican and Democratic presidential candidates, Senators McCain and Obama. Mr. Obama and Senator Clinton are scheduled to address the Aipac conference this morning.