alestinians that “it is obvious that the Palestinian Authority and the Arab countries are leaning towards going to the General Assembly,” where a successful vote could elevate the status of the Palestinian Authority from nonvoting “observer entity” to “observer state,” a status equal to that of the Holy See.

Earlier in the day, Prime Minister Recep Tayyip Erdogan of Turkey ratcheted up pressure on the United States and Israel by telling Arab League ministers that recognition of a Palestinian state was “not a choice but an obligation.”

In Washington, Secretary of State Hillary Rodham Clinton announced that American negotiators would return to the region on Wednesday to meet with Prime Minister Benjamin Netanyahu of Israel and President Mahmoud Abbas of the Palestinian Authority in a final effort to avert a vote on the matter.

The administration, working with the European Union’s foreign policy chief, Catherine Ashton, and Tony Blair, who serves as a special envoy to the region, continued to seek international support for what Mrs. Clinton described as “a sustainable platform for negotiations” between the Israelis and the Palestinians to create a Palestinian state.

She did not elaborate, but the administration hopes that a negotiated agreement on a prospective deal could avert a vote at the United Nations — or even be submitted for approval by the Security Council or the General Assembly in lieu of a Palestinian request for either membership or status as an observer state, administration officials said.

“We all know that no matter what happens or doesn’t happen at the U.N., the next day is not going to result in the kind of changes that the United States wishes to see that will move us toward the two-state solution that we strongly support,” Mrs. Clinton said Tuesday. “The only way of getting a lasting solution is through direct negotiations between the parties, and the route to that lies in Jerusalem and Ramallah, not in New York.”

The administration has spent months trying to avoid casting its veto in the Security Council to block membership of a Palestinian state. It also hopes to avert a vote for the more symbolic change in status in the General Assembly, which senior officials, echoing the Israelis, have warned would be harmful to Israeli-Palestinian peace and could foment violence.

But with negotiations long stalled, the Palestinians and their allies say that such a vote would preserve the idea of a two-state solution.

The timing of the confrontation has created a diplomatic quandary for President Obama, putting him in the position of opposing Palestinian aspirations for self-determination even as his administration has championed Arabs who have overthrown leaders in Egypt, Tunisia and Libya or who seek to in Syria. At the same time, he faces pressure from Israel’s vocal supporters in Congress to block the vote or cut off military and economic assistance the United States has given to the Palestinians.

Internationally, however, the United States and Israel appeared increasingly isolated, with even some European nations, from Russia to France, signaling support for at least a General Assembly vote for the Palestinians.

The support for the Palestinians from the Turkish prime minister was not a surprise, but the commanding tone of his endorsement — coupled with Turkey’s souring relations with Israel, once a close ally — underscored the growing sympathy for Palestinian aspirations for sovereignty and statehood.

“Let’s raise the Palestinian flag, and let that flag be the symbol of peace and justice in the Middle East,” said Mr. Erdogan, the increasingly influential leader of a NATO ally. He also took a harsh tone toward Israel, saying it is “the West’s spoiled child.”

The Arab League signaled that it would press the Palestinians to seek a General Assembly vote to elevate the status of the Palestinian Authority from nonvoting “observer entity” to “observer state.” Some Palestinian leaders, though, continued to press for a Security Council vote.

Although a vote in the General Assembly would not formally recognize a state of Palestine, it would give the Palestinians rights to observe and submit resolutions and join other United Nations bodies and conventions. It could also strengthen their ability to pursue legal cases in the International Criminal Court, something that alarms Israel and the United States in particular.

But the Palestinians also seemed open to the compromise being brokered by Mr. Blair and the American envoys, David M. Hale from the State Department and Dennis B. Ross from the National Security Council.

A top negotiator for the Palestinian Authority said Tuesday night that its leadership was considering strong appeals by the Arab states and the Europeans to turn to the General Assembly, where it is certain to have majority support, and not the Security Council, where the United States can veto any resolution.

The negotiator, Saeb Erekat, added that Mr. Abbas told Arab ministers that the Palestinian Authority had not yet decided, suggesting that it was still considering its options. Mr. Abbas is expected to go to Amman, Jordan, on Wednesday to discuss the issue with Mr. Blair. Mr. Blair and the Europeans “said they have some ideas, and we are waiting to see the ideas formulated,” Mr. Erekat said.

“We don’t intend to confront the U.S., or anyone else for that matter,” he added. “We want to present the United Nations vote as an opportunity for all of us to preserve the two-state solution.”

Mr. Abbas and his Arab allies argue that Israel’s unwillingness to take sufficient steps to create a state of Palestine had obviated the path laid out in the Oslo peace accords of 1993. Mr. Araby said that a United Nations vote would “change the Israel-Palestinian conflict” and become an important step toward a resolution. “It will turn from a conflict about existence to a conflict about borders,” he said.

Some European diplomats have agreed, but urged the Palestinians to turn to the General Assembly because they argued that its approval was more likely to facilitate negotiations rather than a vetoed bid at the Security Council. Mr. Araby said that Ms. Ashton, the European Union’s chief diplomat, expected strong European support for an elevation of the Palestinians’ status to “observer state.”

The consequences of that, however, remained unclear. In Congress, senior Republican lawmakers have introduced language in an appropriations bill that would sever American aid to the Palestinians if they proceeded with the vote. Representative Kay Granger, a Republican from Texas who is the chairwoman of the House appropriations subcommittee that overseas foreign aid, said she had explained that view personally to the Palestinian prime minister, Salam Fayyad, during a visit to Israel and the West Bank last month.

“It’s very bad,” Ms. Granger said of the Palestinian bid at the United Nations. “If they take that step, then we no longer fund. We stop our funding because our position is that it stops the peace process — because they are going outside the peace process.”

She called the expected confrontation in New York next week “a train wreck coming.”

Steven Lee Myers reported from Washington, and David D. Kirkpatrick from Cairo. Heba Afify contributed reporting from Cairo.