WASHINGTON – President Bush ended America’s four-year freeze of the Palestinian Arab leadership yesterday, welcoming Mahmoud Abbas to the White House, offering $50 million in aid, and pressing the Israelis to halt the building of new settlements on the West Bank.

Standing side-by-side with the Palestinian Arab leader in the White House Rose Garden, Mr. Bush said it was critical that this summer’s Israeli withdrawal from Gaza marked the beginning of a renewed peace process and not the end.

Mr. Bush said America would oppose any attempt to break the West Bank into pieces. “A [Palestinian] state of scattered territories will not work. There must also be meaningful linkages between the West Bank and Gaza,” he said.

He pledged to dispatch Secretary of State Rice to the region to meet Mr. Abbas and the Israeli prime minister, Ariel Sharon, to ensure that the Gaza pullout becomes the first step in a renewed commitment to the road map agreement.

Mr. Abbas gave warning that time for a deal was limited. “We must end the Palestinian-Israeli conflict before it is too late,” he said.

But the significance of yesterday’s meeting was as much in the symbolism as in the content.

In final years of the first elected Palestinian leader, Yasser Arafat, who died in November, the Bush White House had effectively severed relations.

Loathed as a double dealer with uncomfortably close ties to terrorists, Arafat became the main block on American involvement in the peace process. Things could not have been more different yesterday. Mr. Bush saluted a smiling Mr. Abbas in a sunlit Rose Garden as “a man of courage” and pledged American support, both political and financial.

The spectacle of the president backing the Palestinian Arab leader will have generated quiet satisfaction in London, where the government has been pressing for greater American involvement in the Israeli-Palestinian question.

The pledge of $50 million for house building and infrastructure repair is a fairly minor point, but it marked a renewed American willingness to hand cash to the Palestinian Authority, which has been severely damaged by evidence of corruption.

But the praise and the gift contained a warning. Mr. Bush said he would stand with Mr. Abbas to “combat corruption, reform the Palestinian security services and your justice system, and revive your economy.” It was made clear that Mr. Bush’s remarks were a shopping list of American expectations from the Palestinian Arab leadership.

Mr. Bush also issued a long list of expectations for Israel. The Israelis should ease restrictions on Palestinian humanitarian needs, remove unauthorized outposts, halt settlement expansion in the West Bank, and ensure that the barrier between Israelis and Palestinians did not become a de facto border.

Ultimately, Israeli troops should return to the dispositions they held on September 28, 2000, the outset of the latest round of violence.

“We’ve got a fantastic opportunity,” said Mr. Bush. “And I told the president [Mr. Abbas] there’s no doubt in my mind we can succeed.”