US Secretary of State John Kerry made a last-minute push on Sunday to revive Middle East peace talks as Israeli media said that days of exhaustive shuttle diplomacy had failed to break the deadlock.
Kerry has spent 13 hours with Israeli Prime Minister Benjamin Netanyahu since Thursday, with the latest session between the two men and their aides lasting until nearly 4 am (0100 GMT) at a hotel suite overlooking Jerusalem's Old City.
A sleep-deprived Kerry was to head to Ramallah in the West Bank on Sunday morning to consult for the third day in a row with Palestinian president Mahmud Abbas, a US official said. His previous two meetings with Abbas took place in Amman.
Israel's army radio painted a grim picture of Kerry's initiative, saying that he has apparently failed in his goal of coaxing the sides back into direct negotiations after a gap of nearly three years.
The Palestinian leader is pushing Israel to free the longest-serving Palestinian prisoners as a sign of commitment to peace, to remove roadblocks in the West Bank and to publicly agree to making the borders that existed before the 1967 Middle East war the baseline for negotiations.
Army radio said that Netanyahu was willing to consider just the first two conditions -- but only after talks were under way, and even then in stages.
So far, Israel has flatly refused to countenance any return to the 1967 borders.
Army radio also said that despite Kerry's efforts, an Israeli committee was likely to push through a big discount for buyers of nearly 1,000 new homes which are due to be built in annexed east Jerusalem.
The committee is due to meet on the issue on Monday. Last week, on the eve of Kerry's arrival, another local committee gave final approval to build some 70 homes in the same area.
As news of the plans reached Ramallah, Palestinian chief negotiator Saeb Erakat said they showed which side was blocking a return to the negotiating table.
"This is Netanyahu's response to everything Kerry said, to his ideas and to all his efforts," Erakat told AFP.
"We on the Palestinian side tried every possible effort to help Kerry succeed but it is obvious today ... that Netanyahu is putting an obstacle in front of Secretary Kerry's efforts."
Kerry, who is wrapping up his fifth visit to the region since taking over the State Department in February, has made the elusive goal of Middle East peace a top priority.
But he is running against the clock.
Kerry is scheduled to attend a meeting of southeast Asian leaders in Brunei on Monday, at which he will also hold talks with Russian Foreign Minister Sergei Lavrov on the Syrian crisis and a row over the presence in Moscow of US leaker Edward Snowden.
He had been due to fly to Abu Dhabi on Saturday for a meeting on the Syria crisis, but cancelled his plans to spend more time shuttling between Netanyahu and Abbas.
Before Kerry leaves on Sunday, he is expected to make a statement on his four-days of shuttle diplomacy, US officials said.
"Kerry is willing to put in the legwork necessary to move this process forward in a meaningful way," a US official said on condition of anonymity.
US officials have been tight-lipped about the substance of Kerry's meetings, fearing that any public statements could put at risk his efforts.
On Kerry's all-night meeting with Netanyahu, a US official said only that the two discussed a "wide range of issues related to the peace process" over a dinner of hummus, pita and sea bream.
Netanyahu had a tense relationship with President Barack Obama during the US leader's first term, with the Israeli premier resisting calls to renew a settlement freeze in order to revive peace efforts.
Israel had observed a 10-month freeze on new West Bank construction which expired shortly after direct negotiations began in September 2010, with the renewal of settlement building causing the talks to collapse.
While some ministers and aides have described Netanyahu as increasingly pragmatic, he emerged from January elections with a coalition of hardliners, many of whom oppose a Palestinian state.
Economy Minister Naftali Bennett, who heads the far-right Jewish Home party, recently described the Palestinian issue as "shrapnel in the buttocks" -- a problem Israel simply had to keep suffering through -- but threatened to quit if the government agreed to a Palestinian state.
Abbas too faces internal dissent, with the Islamist Hamas movement, which controls the impoverished Gaza Strip, strongly criticising him for pursuing talks.