A Hamas official said Israel’s delay in the release of some 600 Palestinian prisoners constitutes a “serious violation” of the ceasefire agreement, and suggested that talks on a second phase of the accord are not possible until they are returned.

As part of the agreement, Israel was supposed to release the prisoners last weekend after Hamas freed hostages from its October 7 2023 attack. But Israel delayed the release over the treatment of the captives, who were paraded before crowds.

In a written statement, Bassem Naim, a senior Hamas official, said the militant group had “fully adhered to all provisions of the agreements” and that Israel’s delay “puts the agreement at risk of collapse, potentially leading to a resumption of war”.

The first phase of the ceasefire is due to end Saturday, and while negotiations on a second phase were to have started weeks ago, they have not yet begun.

A US diplomat is returning to the region this week with the hope of extending the first phase to buy time for further negotiations, but Mr Naim suggested Hamas was unwilling to talk until the prisoners were released.