WASHINGTON — U.S. President Barack Obama and the leaders of Israel and the Palestinian Authority on Wednesday vowed to try to strike a Middle East peace deal within a year, setting high expectations for an agreement that has proven elusive for decades.

During a White House ceremony ahead of direct peace negotiations on Thursday in Washington, Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas offered to put aside decades of mistrust in pursuit of a two-state solution.

"President Abbas, you are my partner in peace. And it is up to us, with the help of our friends, to conclude the agonizing conflict between our two peoples," Netanyahu said to his Palestinian counterpart ahead of a White House dinner hosted by Obama.

"We don't seek a brief interlude between two wars . . . we seek a peace that will end the conflict between us, once and for all."

Abbas, in turn, said he would "spare no effort" to end the lengthy conflict between Israelis and the Palestinians.

Meanwhile, Hamas claimed responsibility early Thursday for another attack in the political hub of the West Bank. Two Israelis were injured Wednesday in the shooting in Ramallah, Agence France-Presse reported. It was the second attack this week.

On Tuesday night, four Israelis were killed in a shooting in another West Bank community.

Hamas — the Islamist group that is opposed to the talks between Netanyahu and Abbas — also claimed responsibility for that attack.

Netanyahu and Abbas will resume long-suspended negotiations Thursday at the U.S. State Department, amid signs that one of the most contentious obstacles to a deal — the future of Jerusalem — may now be on the table.

With Obama appealing for compromise on both sides, Israeli Defence Minister Ehud Barak said Israel might be willing to turn over parts of East Jerusalem to the Palestinians.

"The Arab neighbourhoods in which close to a quarter million Palestinians live will be theirs," Barak told the Haaretz newspaper.

Barak added that Israel intended to retain control of West Jerusalem and a dozen Jewish neighbourhoods in the predominantly Arab eastern part of the city.

An aide to Netanyahu later downplayed Barak's remarks, telling the Agence France-Presse news agency that "our position is that Jerusalem will remain the undivided capital of Israel."

Still, the remark might be a sign of possible Israeli flexibility as direct negotiations between the two sides resume for the first time since December 2008.

Israel seized control of East Jerusalem in 1967 and has long rejected Palestinian demands that East Jerusalem become the capital of a future sovereign Palestine.

The Israeli-Palestinian talks represent a significant diplomatic gamble for Obama, who has set the ambitious goal of a final status agreement by September 2011.

"Both sides have indicated that these negotiations can be completed within one year," Obama said.

Abbas, in an interview Wednesday with an Arab newspaper, said the timetable was not too ambitious. "One year is very long," he said.

The two sides have remained at odds on all major issues — from Jerusalem and Israeli settlements in the West Bank, to borders, security for Israel and the Palestinian's demands for the right of return of refugees.

Obama said he expected the upcoming talks to be "extraordinarily complex and extraordinarily difficult."

Jordan's King Abdullah and Egyptian President Hosni Mubarak were invited to the White House on Wednesday night to help facilitate.

Obama said he believes both Netanyahu and Abbas "want peace" and have taken important steps to give the new round of negotiations a chance at success.

"We are under no illusions . . . years of mistrust will not disappear overnight," Obama said. "This moment of opportunity may not soon come again. They cannot afford to let it slip away."

The challenges in crafting a deal under the tight one-year deadline became evident earlier this week when Hamas extremists claimed responsibility for the killing of four Israeli settlers near Hebron in the West Bank.

Obama condemned the "senseless slaughter" of the Israeli civilians and said it was a sign Hamas was purposely trying to derail the peace talks.

"There are going to be extremists and rejectionists who, rather than seeking peace, are going to be seeking destruction," Obama said. "But I want everybody to be very clear: The United States is going to be unwavering in its support of Israel's security and we are going to push back against these kinds of terrorist activities."

One of the immediate threats to the success of talks is a Sept. 26 deadline for the end of its moratorium on settlement expansion in the West Bank. Netanyahu has so far refused to say whether he will agree to requests from Abbas for the freeze to be extended.

Even if a peace deal is struck in the next year, Abbas and Netanyahu face skepticism about whether they would be able to implement an agreement.

Abbas is hamstrung by the violent resistance to peace by Hamas, which controls Gaza, while the Israeli prime minister faces opposition from right-wing Israelis who reject the notion of a sovereign Palestine.

Despite the obstacles, aides to Obama said the U.S. president became convinced there was a chance for significant progress after holding summer meetings with both Netanyahu and Abbas.

George Mitchell, Obama's special envoy to the Middle East peace process, said Netanyahu has stated privately that he hopes to meet with Abbas as often as every two weeks in a bid to maintain momentum in the talks.

"We think that's a sensible approach, which we hope is undertaken," Mitchell told reporters.

The U.S. will advocate "intensive" negotiations and will play an "active and sustained role" in facilitating the talks, Mitchell said. "That does not mean that the United States must be physically represented in every single meeting."

Added Obama: "Ultimately the United States cannot impose a solution and we cannot want it more than the parties themselves . . . We cannot do it for them. We create the environment and the atmosphere for negotiations."