Ministers said Thursday that Israel would have difficulty approving a scheduled release of Palestinian prisoners if their leadership refuses to extend peace talks beyond an April deadline.

Israel committed to the release of 104 Palestinian prisoners in four tranches when talks were launched in July. It has so far released 78 of those in three batches, with Palestinians demanding the fourth -- scheduled for later this month -- include Arab Israelis as well.

"As long as we don't know what is happening -- if the talks will be extended -- it will be difficult for Israel to approve a move as dramatic as releasing Arab Israelis in the fourth tranche," an aide to Science Minister Yaakov Perry quoted him as saying.

After a three-year deadlock, the US brought the two sides back to the negotiating table with a nine-month timeframe for an agreement.

Washington is now focused on trying to set down a framework for an agreement before the deadline with guiding principles for each of the core issues.

"Israel will have to be certain the talks are continuing to approve the fourth release," said Perry, who used to head the Shin Bet internal security agency.

Foreign Minister Avigdor Lieberman said: "We think the negotiations should be extended to the end of the year at least."

Asked in an interview with the Israeli parliament's television channel whether the government would approve the fourth prisoner release, Lieberman said he didn't "see any chance, if it's not clear beforehand that the negotiations will continue till the end of the year".

"If there's no change in tone and attitude, there's no point in releasing them," he said.

US President Barack Obama is to host Palestinian president Mahmud Abbas at the White House on Monday after similar talks with Israeli Prime Benjamin Netanyahu earlier this month.

"We hope that by the end of next week we will be informed that we've progressed from indirect negotiations through the Americans to direct talks," Lieberman said.

Abbas has said the Palestinians will not agree to extend the negotiations without Israel releasing more prisoners and halting settlement construction in the occupied West Bank