Secretary of State Hillary Rodham Clinton embarked on her first foray into Middle East diplomacy on Monday, offering a pledge of $300 million for war-torn Gaza and urging accelerated efforts for peace.

Mrs. Clinton was attending an international donors’ conference in this Egypt resort on the Red Sea that may well prove to be the simplest part of a visit to a region shadowed by deep mutual distrust between Israelis and Palestinians and the still-unresolved political situation in Israel.

“The United States is committed to a comprehensive peace between Israel and its Arab neighbors and we will pursue it on many fronts,” Mrs. Clinton said. “So too will we pursue a two-state solution” between Israelis and Palestinians.

“Time is of the essence, we cannot afford more setbacks or delays,” she said. It is “not the time for recrimination,” she added, but “the time for looking ahead.”

She said the pledge of American aid to Gaza was “meant to accelerate, not hinder” peace efforts. “Assistance for the Palestinians is one step up the ladder” toward a comprehensive peace, she said.

On Tuesday and Wednesday, Mrs. Clinton will travel to Jerusalem and the West Bank, as the Obama administration shows it is determined to pursue robust, sustained peacemaking efforts, after years of neglect and belated engagement on the part of the Bush administration.

The United States has promised an additional $600 million to the Palestinian Authority to cover a budget shortfall and bolster the Palestinian economy. Some of that money may also end up in Gaza, large parts of which are in ruins after Israel’s military assault on the militant group Hamas. But much of it will go to the West Bank, where the Palestinian Authority is in control.

“Everyone is in agreement that we need to shore up the Palestinian Authority,” said Robert A. Wood, the acting State Department spokesman. “We don’t want that money to go through Hamas.”

During her meetings with Palestinian leaders in the West Bank, Mrs. Clinton will hear anger over Israel’s ongoing construction of Israeli settlements on occupied land there. Nearly 300,000 Israelis live in such settlements in addition to another 250,000 in East Jerusalem, also on land captured in the 1967 war. The Palestinians hope to build their state on that land and argue that settlement building drives that goal further and further away.

Peace Now, an Israeli advocacy group that opposes settlements and monitors their building closely, issued a report on Monday alleging that tens of thousands of new settlement housing units are in the planning stage. The report, clearly issued to coincide with Ms. Clinton’s arrival, said that some 6,000 new units have been approved and another 58,000 are awaiting approval. “If all the plans are realized,” the report said, “the number of settlers in the territories will be doubled.”

Benjamin Netanyahu, the Likud leader who is putting together the next Israeli government, may end up with a narrow right-wing coalition that favors settlement expansion. Nonetheless, Mr. Netanyahu has said he would oppose building any new settlements, although he favors expanding existing ones. A Housing Ministry spokesman, Kobi Bleich, characterized the Peace Now report as alarmist, saying it confused potential building sites with actual plans.

As the United States tries to give new momentum to the peace process, the role of Hamas remains a sticking point. Several European countries are more open to dealing with the group, provided it becomes part of a so-called unity government with the Palestinian Authority.

The United States and Israel, however, will not deal with Hamas, saying it is a terrorist organization bent on the destruction of Israel. And Israel has kept border crossings to Hamas-controlled Gaza closed — prompting criticism that it is blocking desperately needed relief.

“The big question is: What is U.S. policy toward Hamas?” said Martin Indyk, a former American ambassador to Israel who advised Mrs. Clinton on Arab-Israeli issues during her presidential campaign.

Publicly, not much has changed. On Friday, Mrs. Clinton restated Washington’s demand that Hamas renounce terrorism and recognize Israel as a condition for dealing with the United States.

But the Obama administration is not discouraging talks between the Palestinian Authority and Hamas to form a unity government. A senior American official said that if such a government was formed, the United States would not rule out dealing with it, in some fashion.

Such openness, Mr. Indyk said, would be a significant shift in policy from the Bush administration, which had focused on buttressing the Palestinian Authority in the West Bank and isolating Hamas in Gaza.

Administration officials cautioned, however, that conditions remained hostile to peace, with Hamas militants launching more rockets at Israeli towns. In Israel, Mr. Netanyahu may end up forming a narrow right-wing government, even less inclined to dealing with Hamas.

With so many impediments to an Israeli-Palestinian deal, analysts say the more promising avenue may be an opening to Syria. The State Department invited Syria’s ambassador to the United States, Imad Moustapha, to a two-hour meeting on Thursday, which might serve as a first step toward engagement.