WASHINGTON — President Bush sought yesterday to intensify Middle East peace efforts, announcing that his administration would release more money to the Palestinian Authority and would host a meeting of Israeli and Arab leaders this fall.

Mr. Bush, who has been trying to bolster the Palestinian Authority president, Mahmoud Abbas, said the financial and diplomatic help would be aimed at building Palestinian institutions and backing for a moderate course that he said could lead to the creation of a Palestinian state.

In a brief speech at the White House, Mr. Bush said the takeover of the Gaza Strip by the militant group Hamas had left the Palestinian Arab people with a clear choice between violent radicalism and moderation.

“This is a moment of clarity for all Palestinians,” Mr. Bush said. Mr. Bush said America would provide $190 million this year to the Palestinian government. It was not immediately clear whether that money was entirely a new commitment or whether it included previously committed funds. Since the Gaza takeover, America and Western allies have agreed to try to isolate the Hamas government while building up the Abbas government, which remains in command on the West Bank. But critics say that the strategy is a long shot, because the authority is weak, and that Western support may only alienate average Palestinian Arabs.

Critics also question whether financial support may be enough to strengthen Mr. Abbas. They say his chances for success will depend on whether Israel is willing to make major concessions on issues such as travel and West Bank settlements that the weak Israeli government is unlikely to make. Mr. Bush was originally scheduled to give his speech three weeks ago, on the fifth anniversary of the 2002 speech in which he called for creation of two states, Israeli and Palestinian, living in peace. But the speech was postponed because of the Gaza takeover. Israel welcomed Mr. Bush’s call for a peace conference.

“We share his vision of two states, Israel and Palestine, living side by side in peace,” an Israeli Foreign Ministry spokesman, Mark Regev, said. “We believe the way forward is to engage with the moderates and to have a no-tolerance policy toward terrorism.”

Israel, in the past, has been averse to multilateral peace conferences, preferring instead to deal through American mediators or directly with the Palestinian Authority. Mr. Regev said Israel “supports multilateral efforts to strengthen the Israeli-Palestinian dialogue.”

“We believe it’s very important that the moderate, pragmatic states of the region play a more energetic role in supporting the peace process,” he said.

As for new American aid to the Palestinian Authority, Mr. Regev said Israel, like America, would seek safeguards to make sure the money “does not end up with terrorists “