President Obama called on Israelis and Palestinians on Thursday to move swiftly toward peace talks, as his administration embarked on its first public dispute with Israel.

Speaking to reporters at the White House after talks with the Palestinian president, Mahmoud Abbas, Mr. Obama said that the absence of peace between Israelis and Palestinians was clogging up other critical issues in the Middle East.

“Time is of the essence,” Mr. Obama said. “We can’t continue with the drift and the increased fear on both sides, the sense of hopelessness that we’ve seen for too many years now. We need to get this thing back on track.”

Mr. Obama reiterated his call for a halt to Israeli settlements in the West Bank, and said he expected a response soon from Prime Minister Benjamin Netanyahu of Israel.

Mr. Obama’s words echoed — albeit less bluntly — Secretary of State Hillary Rodham Clinton’s brusque call on Wednesday for a complete freeze of construction in settlements on the West Bank. In expansive language that left no wiggle room, Mrs. Clinton said that Mr. Obama “wants to see a stop to settlements — not some settlements, not outposts, not natural growth exceptions.”

Her comments took Israeli officials by surprise.

Mr. Obama said something similar last week during private talks with Mr. Netanyahu at the White House, and Mr. Netanyahu responded that he could crack down on outposts, but not on the natural growth of settlements, according to American and Israeli officials.

The administration then took the quarrel public, laying down the marker that allowing natural growth would not satisfy the United States and that administration officials would not limit themselves to the diplo-speak of the past that simply called settlement expansion “unhelpful.” The decision left the two allies hurtling toward their first public fight.

On Thursday, Mr. Netanyahu’s spokesman, Mark Regev, said that “normal life” would be allowed in settlements in the occupied West Bank, using the phrase that Israel often uses to describe continued construction to accommodate population growth.

Privately, Israeli officials said they were upset by the administration’s hard line. Israel’s defense minister, Ehud Barak, is scheduled to visit Washington next week with Israel’s response to Mr. Obama’s call for a settlement freeze, American officials said.

Advisers to the Palestinian Authority said that Mr. Abbas’s meetings in Washington with administration officials — including Mrs. Clinton and the national security adviser, Gen. James L. Jones — had been more amicable than the Israelis’ meetings were. That could reflect the view in Washington that Mr. Abbas does not have the political weight at the moment to push through anything on the Palestinian side.

Part of the reason administration officials are pushing the Israelis on settlements is that they think that stance will bolster Mr. Abbas, who has an increasingly fractured Palestinian population. Mr. Obama congratulated Mr. Abbas for adhering to the West’s argument that he should not form a national unity government with the militant Islamist organization Hamas until Hamas forswears violence and recognizes Israel’s right to exist.

Several American presidents, from Ronald Reagan to George W. Bush, have called on Israelis to halt settlement activity, to no avail. The question now, Middle East experts said, is how far Mr. Obama is willing to go to make that happen.

“Hillary Clinton’s statement was notable because the language was stronger than we’ve heard in years,” said Ali Abunimah, the co-founder of ElectronicIntifada, a Web site that analyzes the Israeli-Palestinian conflict. “And clearer than we’ve heard in years. But the burden of proof is still on them. If it’s just going to be strong statements, that’s not enough.”

Administration officials have not said whether there is an “or else” attached to their demand for a settlement freeze.

Mr. Obama said Thursday that it was not yet time for that. “In my conversations with Prime Minister Netanyahu, I was very clear of the need to stop settlements, stop the building of outposts,” he said. “I think we don’t have a moment to lose, but I don’t make decisions based on a conversation we just had last week.”

Administration officials are trying to elicit support for Mr. Obama’s stance from pro-Israel lawmakers in Congress, including Senator John Kerry, the Democrat of Massachusetts who is chairman of the Foreign Relations Committee.

If they can expand that support to include House members like Gary Ackerman and Nita M. Lowey, both Democrats of New York, then Mr. Netanyahu could find himself on the defensive at home for allowing Israel’s relationship with its most powerful backer, the United States, to sour, foreign policy experts said.

“This approach is predicated on the assumption that an Israeli prime minister needs a tough American president to justify tough decisions to an Israeli public,” said Martin Indyk, director of the Saban Center for Middle East Policy and a former United States ambassador to Israel. “People in the American Jewish community and in Israel are sick of settlement activity. The whole zeitgeist has changed.”