US Secretary of State John Kerry urged Israeli and Palestinian leaders on Friday to take "hard decisions" to revive the Middle East peace process, which has stalled for almost three years.
Kerry has been pressing Israel and the Palestinians to resume direct peace talks that broke down in September 2010, notably over the issue of Jewish settlement building.
"We're getting toward a time now when hard decisions need to be made," he told a news conference in Tel Aviv at the end of his fourth visit to the region since he took office in February.
He said there was "one way" to make peace a reality, "and that is through direct negotiations.
"Ultimately it is the Israeli and Palestinian people who both decide the outcome... and who will get the greatest benefits" from a resumption of talks, he said.
Meeting Palestinian president Mahmud Abbas in Ramallah in the West Bank and Israeli Prime Minister Benjamin Netanyahu in Jerusalem on Thursday, Kerry admitted there was scepticism and cynicism about his bid to broker new talks.
"I know this region well enough to know there is scepticism, in some quarters there is cynicism, and there are reasons for it. There have been bitter years of disappointment," he said.
But he insisted: "It is our hope that by being methodical, careful, patient, but detailed and tenacious, that we can lay on a path ahead that can conceivably surprise people and certainly exhaust the possibilities for peace."
And in a powerful message to Palestinians, who are used to just seeing American motorcades sweep by into Abbas's high-walled headquarters compound, Kerry went for a stroll along a Ramallah street.
Despite public pronouncements of support, there is growing frustration that there has been little sign of a shift in the long-held positions of the two sides.
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Complicating efforts is the new Israeli government, which has moved more towards the right and includes some ministers who oppose a two-state solution.
Kerry also warned on Friday that there was a time limit on the possibility of peace, after Thursday comments from British Foreign Secretary William Hague -- also on a visit to the region -- that the prospects of a two-state solution "cannot be kept alive forever."
"It is clear that in the long run the status quo is not sustainable," Kerry said.
The secretary of state also touched on the sensitive issue of Jewish settlement building in the Palestinian territories, one of the principal issues over which the 2010 talks stalled.
"The US position on settlements is clear and has not changed... we believe they should stop," he said.
"Some things are beyond control... but certainly the (Israeli) government has the ability to make a difference here in the next months. It is my hope that they will."
Israel has come under mounting international criticism for ramping up construction in the settlements.
Settlements in the West Bank, including annexed Arab east Jerusalem, are illegal under international law.
Palestinians demand a freeze on settlement construction before they will return to the negotiating table.
But Kerry stressed the priority was for talks "without preconditions."