Israeli Prime Minister Benjamin Netanyahu’s national security adviser says a planned hostage-for-prisoner swap with Hamas has been delayed until at least Friday, Paralel.Az reports citing Associated Press.

In a statement released late Wednesday, Tzachi Hanegbi said that contacts on the deal were continuing. “The release will begin according to the original agreement between the parties, and not before Friday,” he said.

The swap is to take place as part of a four-day truce expected to begin on Thursday.

Hanegbi gave no explanation for the delay, and it was not immediately clear when the cease-fire might begin.