The Palestinian extremist group Hamas has sharply criticized Israel for delaying the release of Palestinian prisoners in return for the earlier handover of six Israeli hostages.

Hamas has informed mediators Egypt and Qatar, about the delay, according to a statement by organization.

Hamas warned that Israel would no longer find mediators for the conflict if it violated the agreement and refused to release the prisoners.

The release of more than 600 Palestinian prisoners had still not begun several hours after Hamas handed over the sixth Israeli Gaza hostage to the International Committee of the Red Cross (ICRC). In previous exchanges, the Palestinians were released soon after the Israeli hostages returned home.

Israel did not initially explain the reasons for the delay.

Israeli media reported, citing unnamed Israeli officials, that Prime Minister Benjamin Netanyahu wanted to hold security consultations on how to proceed before the release. The first phase of the ceasefire is expected to end in a week, and talks on the second phase have reportedly not yet begun.