The Palestinians on Wednesday threatened to resume their campaign for international recognition at the United Nations if Israel calls off a planned release of Palestinian prisoners, deepening a crisis that has threatened to derail US-led Mideast peace efforts.
As part of US efforts to revive peace talks with the Palestinians talks frozen for three years, Israel pledged to release 104 long-serving prisoners jailed for attacks, many of them deadly, against Israelis before a 1993 interim peace deal.
So far, 78 prisoners have been released in three stages. The fourth and final group is to be released by March 29. But the talks have made little progress and Washington is trying to set guidelines to keep them going beyond the original April 29 target date for an accord.
On Monday, Palestinian Authority President Mahmoud Abbas told US President Barack Obama that the release of the fourth and last group of prisoners would show Israel's "seriousness" towards the peace talks.
But in recent days, Israel has signaled it may not carry out the final release. Chief peace negotiator Tzipi Livni said Tuesday that Israel is not obligated to free the prisoners, and said the decision to do so would depend on progress in peace talks. Israel is seeking a Palestinian pledge to extend talks beyond a current April deadline.
"There was never any automatic commitment to release prisoners unrelated to making progress in negotiations," Livni said in a speech in southern Israel that could complicate Washington's efforts to salvage peacemaking.
Palestinian official Nabil Shaath said Wednesday that the Palestinians would "immediately" resume their UN campaign if Israel reneges on the release. The Palestinians froze these efforts as part of the US-brokered package that relaunched the negotiations last year.
"We committed to not applying to the UN agencies and Israel committed to release 104 ... prisoners in four batches," he said. "That was the deal. If Israel breaches it, we will too."
An Israeli official, speaking on condition of anonymity, said that Israel wanted assurances that Abbas wouldn't walk out of the talks once the prisoners went free.
Netanyahu, who met Obama in Washington two weeks ago, has said any peace deal with the Palestinians would take at least another year to negotiate should both sides accept US-proposed principles to keep the talks going.
"We need to be sure the negotiations will last beyond the release of prisoners, and that they will be substantive, and on solid ground," the official said.
The issue of prisoners is deeply emotional for both Israelis and Palestinians.
The Palestinians consider the 5,000 prisoners held by Israel to be heroes in the struggle for independence. Prisoners freed in previous releases have received jubilant welcomes upon their return.
Israel considers the prisoners to be terrorists. The people freed in the previous releases had all served lengthy sentences for participating in bloody attacks on Israelis, and the Palestinian celebrations have sparked widespread anger.
Another stumbling block, the official said, is a Palestinian demand that Israeli Arabs convicted of deadly attacks on Jews be included among those due to go free this month.
But Israel may have little choice on the matter. On Tuesday, US State Department spokeswoman Jen Psaki said the US supports the prisoner release. "It's part of what was agreed to between the parties," she said.
In addition, the resumption of the Palestinian at the campaign at the UN could cause new headaches for Israel on the global stage. Israel has condemned the campaign as an attempt to circumvent peace talks.
In 2012, the UN General Assembly granted the Palestinians upgraded "nonmember state" status, clearing the way for them to join various international agencies to pursue an anti-Israel agenda. In particular, Israel fears the Palestinians will try to pursue war crimes charges against Israel in the International Criminal Court.
Associated Press and Reuters contributed to this report.