Israeli-Palestinian peace talks are in crisis after the latest attempt to reconcile key differences failed.

Early Friday morning, a meeting between Palestinian Authority President Mahmoud Abbas and American special envoy Martin Indyk on the scheduled fourth prisoner release ended without a breakthrough.

According to Ziad Abu Ein, director-general of the PA Ministry of Prisoners’ Affairs, the meeting concluded in deadlock. Abu Ein said Israel is still refusing to release a fourth and final group of longterm prisoners, a move that had been scheduled for this weekend, and has introduced new conditions for their release. Abu Ein said Israel conditioned the release on the continuation of talks beyond the current end of April deadline, as well as several demands related to the framework agreement that Secretary of State John Kerry has been drafting as the basis for continued negotiations. Kerry met with Abbas in Amman earlier this week to try to resolve the crisis, without success.

Writing on his Facebook page, Abu Ein accused Israel of violating the agreement in which 104 prisoners are to be released in exchange for the PA not continuing its campaign against Israel and its bid for statehood via the UN and other international institutions. “Israel says ‘yes’ only if the talks continue, and this represents a clear violation,” he charged. Israel has freed three groups totaling 78 prisoners, but balked at the final group because no deal has yet been done on extending the talks and because the PA is demanding that Israeli-Arab inmates be included in the group.

“We will not pay twice,”  added Abu Ein. “For eight months, the killing and settlement building has continued, and, as per our commitment, we didn’t turn to any international institutions [to protest].”

Under a July 2013 deal for the relaunch of the peace negotiations, Israel said it would release 104 Arabs held since before the 1993 Oslo peace accords in exchange for the Palestinians not pressing their statehood claims via the UN.

If the releases do not go ahead as scheduled this weekend, Palestinian leaders are threatening to renew their diplomatic push at the United Nations.

Abu Ein said that the Palestinian leadership emphasized that it will not enter negotiations about the prisoner release arrangements, which were already concluded, and that Israel must fulfill the terms of the deal and release the fourth batch of security prisoners.

The United States has proposed freeing Israeli spy Jonathan Pollard in a trade-off deal in which Israel would agree to proceed with the next round of prisoner releases, including Israeli Arab prisoners, and the Palestinian Authority would agree to extend the current peace talks, Israel’s Army Radio reported Wednesday.

It said the offer had been conveyed to Israel and the PA, but there was no official confirmation. However, State Department spokeswoman Jen Psaki was quoted telling journalists accompanying Secretary of State John Kerry to a meeting with PA President Mahmoud Abbas Wednesday morning that there were currently no plans to release Pollard, who is serving a life sentence.

In exchange for Pollard, Israel would agree to release 26 prisoners, among them around 20 Arab Israelis, and the Palestinians would agree to continue talks until the end of 2014, according to the Army Radio report.

Kerry reportedly made the offer after Prime Minister Benjamin Netanyahu made clear his intentions to cancel the final stage of a prisoner release, previously agreed to as a bargaining chip for starting peace talks this past July, unless Abbas agreed to extend the talks past the upcoming April deadline.

Right-wing Israeli politicians have objected to the prisoner release, particularly the release of inmates who are Israeli citizens, but the inclusion of Pollard in the deal would likely help bring them aboard.