A senior Palestinian official says the Palestinians will resume their campaign for international recognition at the United Nations if Israel calls off a planned release of Palestinian prisoners.

Israel pledged to release 104 long-serving prisoners in four stages under a US-brokered deal to relaunch peace talks with the Palestinians last July. In the first three phases, 78 have gone free. The fourth and final group is to be released by March 29.

Israel’s chief 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.

Palestinian official Nabil Shaath said the Palestinians said if the prisoner release is called off, the Palestinians will “immediately” turn to the UN.

The fate of the roughly 5,000 Palestinian security prisoners is extremely emotional in Israel, where the prisoners are seen as terrorists because many were involved in bloody attacks on civilians. Prisoners freed in previous rounds had been convicted in grisly killings of Israelis, and their releases angered many. Israel also objects to the Palestinian demand that Arab citizens of Israel be included in the final round.

The issue is equally emotional in Palestinian society after decades of fighting Israel. Palestinians view the inmates as heroes, and prisoners freed in previous rounds were embraced by Abbas and welcomed in elaborate celebrations.