Israel and Hamas on Sunday accused each other of violating the already fragile Gaza cease-fire deal after Israel delayed the release of hundreds of Palestinian prisoners who were supposed to be exchanged for hostages.

The office of Israel’s prime minister, Benjamin Netanyahu, said the prisoners would not be freed until the release of further hostages “has been assured,” and Hamas committed to letting them go without “humiliating ceremonies.”

The growing tensions come after a week of mutual recriminations and strained nerves on both sides. The delay raised more questions about the future of the cease-fire for Gaza, with a temporary, six-week truce set to expire at the end of the week.

There is no clarity yet about a possible extension, or even whether serious negotiations have begun. Some members of Israel’s right-wing government are pressing for a resumption of the fighting after the initial phase of the cease-fire, which has provided a brief lull in the devastating war set off by the Hamas-led attack on Israel on Oct. 7, 2023.

On Saturday, Hamas released six Israeli hostages, the last living captives set to be freed in the first phase of the cease-fire. Earlier it had handed over the remains of four hostages, including a mother, Shiri Bibas, and her two young children, who were all taken alive during the October assault. Israel was supposed to release 620 Palestinian prisoners and detainees in return, the largest group of detainees to be let go since the cease-fire in Gaza began last month, but it delayed the move, citing what Mr. Netanyahu’s office described as Hamas’s “cynical exploitation” of the hostages for propaganda purposes.

Hamas has been releasing hostages in performative ceremonies aimed at showing that it is still in control of Gaza, a practice which many Israeli officials have condemned. On Saturday, five of the six living hostages were paraded on a stage, flanked by masked gunmen at theatrical handover ceremonies in Gaza, prompting outrage in Israel. Anger was further inflamed when Hamas published a propaganda video footage on Saturday night showing two other Israeli hostages who had been forced to watch three of their fellow captives being released.

Repeatedly putting their shorn heads in their hands, the pair pleaded, on camera, for their freedom. Rights groups and international law experts say that a hostage video is, by definition, made under duress, and the statements in it are usually coerced. Israeli officials have called past Hamas videos a form of “psychological warfare,” and experts say their production can constitute a war crime.

In a statement early Sunday, Mr. Netanyahu’s office accused Hamas of violating its agreement with Israel and said the prisoner release was postponed “until the release of the next hostages has been assured, and without the humiliating ceremonies.” On Thursday, Hamas is supposed to hand over the bodies of four more deceased Israelis under the terms of the initial phase of the cease-fire.

Izzat Al-Rishq, a member of Hamas’s political bureau, said in a subsequent statement on Sunday that Mr. Netanyahu’s decision to delay the prisoner release “reflects a deliberate attempt to disrupt the agreement.”