Israel has delayed the release of hundreds of Palestinian prisoners citing the “humiliating” circumstances of previous handovers with Hamas.

Prime Minister Benjamin Netanyahu said the prisoners — who were supposed to be freed Sunday, local time — won’t be let go until Israel receives guarantees for their remaining citizens in Hamas custody.

“In light of the repeated violations by Hamas — including the ceremonies that demean our hostages and the cynical use of our hostages for propaganda purposes — it has been decided to delay the release of terrorists planed for yesterday until the next release of hostages is guaranteed, and without the degrading ceremonies,” a statement from the Prime Minister’s Office reads, the Times of Israel reported.

The release of the 620 Palestinian prisoners was supposed to happen just after Israel received six hostages from the group on Saturday.

Five of the six Israeli hostages freed by Hamas on Saturday were escorted by masked, armed militants and marched in front of a crowd. 

On Friday, Hamas, attempting to return the remains of Shiri Bibas, presented the wrong body to Israeli officials. On Saturday, the bodies of Shiri Bibas and her two sons, Ariel and Kfir, were returned to Israeli custody, with officials from the country stating the family was murdered while in captivity in Gaza.

Thus far, as part of the ceasefire deal, Hamas has released 25 living hostages and bodies of four others. There are still 63 Israelis being held by Hamas, with at least two dozen still alive, the Times of Israel reports.

Hamas has released the last six living hostages expected under the conditions of the ceasefire signed last month.

Four more bodies were slated to be released on Thursday, which was the last planned transfer of the first stage of the ceasefire agreement. With this latest development the future of the ceasefire remains in doubt.