Israel has told the Palestinians it will not free the final batch of prisoners they had been expecting alongside US-brokered peace talks, a senior Palestinian official said on Friday.
Under the deal which relaunched the talks in July, 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 at the United Nations.
Israel has so far freed 78 prisoners in three batches but cabinet members had warned they would block the final release, anticipated for the end of March, if the Palestinians refused to extend the talks beyond their April 29 deadline.
"The Israeli government has informed us through the American mediator that it will not abide with its commitment to release the fourth batch of Palestinian prisoners scheduled for tomorrow, Saturday 29," Jibril Rajub told AFP.
"Israel has refused to commit to the names that were agreed upon of prisoners held by Israel since before the 1993 Oslo agreements," Rajub said.
Israeli officials had no immediate comment.
But Israeli ministers have said previously that the prisoner releases were always conditional on progress in the talks, which had failed to materialise.
Many also baulked at the inclusion of Israeli Arabs among the prisoners slated for release.
Rajub called the Israeli move a "slap in the face of the US administration and its efforts," and said the Palestinians would resume their international diplomatic offensive.
"Not releasing the prisoners will mark the beginning of the efforts in the international community to challenge the legality of the occupation," he said.
The talks have been teetering on the brink of collapse, with Washington fighting an uphill battle to get the two sides to agree to a framework for continued negotiations until the end of the year.
US Secretary of State John Kerry met Palestinian president Mahmud Abbas in Amman on Wednesday in a bid to salvage the talks, with US special envoy Martin Indyk meeting the Palestinian leader in Ramallah on Thursday.