US President Barack Obama has urged his Palestinian counterpart Mahmoud Abbas to make tough decisions and take risks for peace with Israel, ahead of a 29 April deadline for US-brokered negotiations.

"We remain convinced there is an opportunity," Obama told reporters as Abbas sat beside him in the Oval Office.

Obama met Israeli Prime Minister Benjamin Netanyahu two weeks ago in Washington and is trying to narrow gaps between the two sides on a framework for a peace deal that would extend negotiations beyond the April deadline.

During the talks on Monday, overshadowed by the Ukraine crisis, Abbas pressed for Netanyahu to go ahead with the scheduled release of a final group of Palestinian prisoners by the end of March, in order to aid the process.

Abbas agreed that a solution should entail a Palestinian state built on borders that existed before the 1967 Middle East war, though Netanyahu has declared that Israel would never completely return to earlier lines it considered indefensible.

US Secretary of State John Kerry brought Israel and the Palestinians back into negotiations on July 29, 2013, after a three-year gap, and said at the time that "our objective will be to achieve a final status agreement over the course of the next nine months".

As the April 29 deadline approaches, US officials have scaled back their ambitions, saying they are now trying to forge a "framework for negotiations" by then.

Kerry himself suggested on February 26 that a full peace deal could take a further nine months.

The two sides do not appear to have made much visible progress on narrowing their gaps on the major issues in the more than six-decade dispute, which include borders, security, the fate of Palestinian refugees and the status of Jerusalem.

"The secretary thanked President Abbas for his steadfast leadership and partnership over the past few months and encouraged him to make the tough decisions that will be necessary in the weeks ahead," a senior State Department official said of their three-hour meeting on Monday, the Reuters news agency reported.

"He also reiterated that we are at a pivotal time in the negotiations and while these issues have decades of history behind them, neither party should let tough political decisions at this stage stand in the way of a lasting peace," the official added, describing Monday's talks as "frank and productive."

PHOTO CAPTION

Palestinian President Mahmoud Abbas listens his meeting with President Barack Obama in the Oval Office of the White House in Washington, Monday, March 17, 2014.

Aljazeera