Israel delayed the release of more than 600 Palestinian prisoners on Saturday after six hostages were freed that afternoon.

Military vehicles that typically move in advance of the buses carrying the prisoners left the prison gates open, before turning around and going back in, The Associated Press reported.

In a statement early Sunday, Israeli Prime Minister Benjamin Netanyahu said Israel would “delay the release of terrorists that was planned for yesterday until the release of the next hostages has been assured, and without the humiliating ceremonies.”

The prisoner release was slated to take place shortly after the hostages were freed in what would have been the largest single-day release of Palestinian prisoners in the first phase of the ceasefire deal.

It was also scheduled to be the final handover of living hostages during the first phase of the agreement. One more handover, involving the bodies of four hostages who died in captivity, is scheduled to take place in the first phase. Negotiations for the second phase of the ceasefire have not yet taken place, the BBC reported.

In his statement, Netanyahu accused Hamas of “repeated violations,” citing specifically “the ceremonies that humiliate our hostages and the cynical exploitation of our hostages for propaganda purposes.”

Five of the six hostages freed Saturday by Hamas were escorted by masked, armed militants in front of a crowd, in a display that the United Nations and the Red Cross have described in the past as cruel.

In one staged ceremony, Omer Wenkert, Omer Shem Tov and Eliya Cohen — who were not soldiers when abducted — posed in fake army uniforms alongside members of Hamas. Shem Tov, acting under duress, kissed two militants on the head and blew kisses to the crowd, the AP reported.

Hamas also released a video showing two other hostages, still in captivity, watching a handover in Gaza and speaking under duress.

Hamas spokesperson Abdel Latif Al-Qanou accused Israel of violating the ceasefire deal, saying Netanyahu was “deliberately stalling.”

The delay also comes after Hamas released the wrong body on Thursday for hostage Shiri Bibas, who was abducted with her two young sons. Hamas said it was a mistake and handed over the correct body on Friday, but Netanyahu vowed revenge for the grueling error, saying it was “a cruel and malicious violation.”

The Associated Press contributed.