Updated

JERUSALEM-- A high-level U.S. team kicked off a new round of shuttle diplomacy on Wednesday in a last-ditch effort to contain the diplomatic fallout from the Palestinian statehood push, but the odds of a breakthrough appeared slim as the Palestinians pledged to go ahead with mass rallies to draw world attention to their bid.

U.S. diplomats Dennis Ross and David Hale arrived late Wednesday for talks with Prime Minister Benjamin Netanyahu and other Israeli leaders. They were to travel to the West Bank on Thursday to talk with Palestinian President Mahmoud Abbas.

Washington is trying to persuade the Palestinians to drop their plan to ask the United Nations to recognize an independent Palestinian state, but so far without success.

The Palestinians are turning to the U.N. after peace talks with Israel broke down, hoping a U.N. bid would boost their statehood drive. Both Israel and the U.S. oppose the campaign, saying there is no substitute for negotiations.

An Israeli official said there was "a very intensive effort" under way in hopes of finding a formula that would allow negotiations to resume. "We hope we succeed. It's not a foregone conclusion," said the official, speaking on condition of anonymity because he was discussing a sensitive diplomatic matter.

More On This...

There was no immediate Palestinian comment. Officials have said they remain determined to go to the U.N. unless Israel accepts their demand for a freeze on West Bank settlement construction and commits to a Palestinian state based on the cease-fire lines that mark the West Bank, east Jerusalem and Gaza -- areas captured in the 1967 Mideast war.

With the odds of a breakthrough appearing slim, the Palestinians plan to submit a resolution to the United Nations during the annual General Assembly, which begins in New York on Tuesday.
Although the vote would not change the situation on the ground, the Palestinians believe U.N. recognition of a state along the 1967 lines would give them leverage in future negotiations.

Netanyahu wants to keep parts of the West Bank under any final peace deal and says that Israel will never relinquish control of east Jerusalem, home to sensitive Jewish, Christian and Muslim holy sites. Israel withdrew from Gaza in 2005.

Israeli-Palestinian talks stalled nearly three years ago, reviving only briefly last September before foundering again over Israeli settlement construction.

Palestinian activists announced Wednesday that they are planning two major demonstrations next week in connection with the U.N. bid: The first will be on Wednesday, and the second will come two days later on Sept. 23, when Abbas is scheduled to address the General Assembly.

The Palestinians say they are determined to keep the rallies peaceful.

"We want to tell world leaders that the Palestinian people seek freedom and independence and need your support," said Amin Maqboul, a senior official with Abbas' Fatah Party.

He said the rallies will take place inside West Bank towns and cities, and avoid Israeli military checkpoints and any other flashpoints like entrances to Israeli settlements. Police will ring the demonstrations to prevent any clashes with the Israelis, Maqboul said.

Israeli security officials are concerned that isolated incidents could touch off more widespread unrest. Soldiers and police have been training for months in preparation for possible violence.

Israeli leaders have also hinted of retaliation, including financial sanctions or the possible annexation of parts or all of the West Bank.

In addition to the U.S. efforts, the European Union's foreign policy chief, Catherine Ashton, and special international Mideast envoy Tony Blair have been meeting with the sides this week. U.S. officials said Secretary of State Hillary Rodham Clinton has been in touch with both Ashton and Blair in recent days.

While Israel has tried to play down the significance of the vote, a setback in the U.N. will add to a growing sense of isolation.

Turkey, a former ally, recalled its ambassador earlier this month after Israel refused to apologize for its May 2010 raid on a Gaza-bound flotilla that killed nine Turks.

A U.N. report released Wednesday praised state-building achievements by Abbas' government but warned they were at risk because of the stagnant political process.

"The reality is that there is only so much that can be done in conditions of prolonged occupation, unresolved final status issues, no serious progress on a two-state solution and a continuing Palestinian divide," said Robert Serry, the special U.N. envoy to the Mideast.

Abbas' Palestinian Authority governs the West Bank, but lost control of Gaza to Hamas militants in 2007. A reunification pact signed in May between the Palestinian factions has not been carried out.