Updated

In a dramatic policy shift, Israel's prime minister has agreed to negotiate the borders of a Palestinian state based on the cease-fire line that marks off the West Bank, according to a TV report.

Up to now, Benjamin Netanyahu has refused to spell out his plan for negotiating the border. A senior Israeli official would not confirm outright that the prime minister was now willing to adopt the cease-fire line as a starting point, but said Israel was willing to try new formulas to restart peace talks based on a proposal made by President Obama.

In a speech about the Middle East in May, Obama proposed negotiations based on the pre-1967 line with agreed swaps of territory between Israel and a Palestinian state. Netanyahu reacted angrily, insisting that Israel would not withdraw from all of the West Bank, though that was not what Obama proposed.

Now Netanyahu is basically accepting that framework, Channel 2 TV reported on Monday, and is offering to trade Israeli territory on its side of the line for West Bank land where its main settlements are located.

The Israeli official, who has been briefed on the talks, spoke on condition of anonymity because the contacts are still in progress. He said he would not deny the TV report, while refusing to confirm the specifics. He emphasized that Israel would not withdraw from all of the West Bank.

"We are willing in a framework of restarting the peace talks to accept a proposal that would contain elements that would be difficult for Israel and we would find very difficult to endorse," he said, answering a question about the Obama proposal.

Part of the reason, he said, was that Israel is seeking to persuade the Palestinians to drop their initiative to win U.N. recognition of their state next month, something the Palestinians are doing out of frustration with stalled peace efforts.

Palestinian officials said they had not received such a proposal from Israel.

Palestinians have demanded that Israel stop construction in its West Bank settlements and east Jerusalem before peace talks resume. Netanyahu wants talks with no preconditions where issues like settlements and borders would be discussed, along with his insistence that the Palestinians recognize Israel as a Jewish state.

The cease-fire line that marks the West Bank dates to the 1949 end of the two-year war that followed the creation of Israel. It held until June 1967, when Israel captured the West Bank, Gaza Strip and east Jerusalem, claimed by the Palestinians.

Palestinians and most of the world consider the 1967 lines a border, while Israel has always held that it was just a temporary truce line that does not dictate the location of the border.

Previous Israeli governments have accepted the cease-fire line as the basis for talks, and the two sides came close to agreement twice in the past decade before talks broke down over other matters.

Thorny issues like sharing Jerusalem and the fate of Palestinian refugees would remain after the border issue is resolved, but U.S. Secretary of State Hillary Rodham Clinton has said that setting a border would defuse the explosive settlement issue by determining which of the enclaves would become part of Israel and which would not.

In the absence of an agreement to return to negotiations, the Palestinians are moving ahead with their U.N. recognition initiative. While a vote in the General Assembly would be symbolic and not legally binding, the Palestinians believe any international endorsement will isolate Israel and improve their position if negotiations resume.

Palestinian officials said Monday they plan to begin mass marches against Israel's occupation of the West Bank on Sept. 20, the eve of the U.N. vote.

Palestinian official Yasser Abed Rabbo said leaders hope to attract millions, and the protest will be the first of a prolonged effort. He said the campaign would be called "Palestine 194," since the Palestinians hope to become the 194th member of the United Nations.

"The appeal to the U.N. is a battle for all Palestinians, and in order to succeed, it needs millions to pour into streets," he said.