Israeli National Security Adviser Tzachi Hanegbi said the release of 50 hostages held by Hamas in the Gaza Strip has been delayed until at least Friday.

According to The Times of Israel, “negotiations for the release of our hostages are constantly moving forward,” Hanegbi added in a brief statement, without elaborating.

Senior Hamas official Musa Abu Marzouq had previously assured Qatar’s Al Jazeera television that the four-day humanitarian truce would take effect this Thursday at around 10:00 am (local time).

In addition, he stressed that the group is “ready for Stop the fire comprehensive and prisoner exchange”, before clarifying that “the majority” of the hostages who will be released “are of foreign nationality.”

According to the agreement, Palestinian militia will hand over 50 hostages, and in return Israel will release 150 prisoners held in its prisons, all of them women and minors under 19 years of age. During the truce, Israeli authorities, who have vowed not to arrest or attack anyone in the Gaza Strip, will completely stop flying over the southern part of the enclave and the northern part for six hours a day.

The pact between the parties also calls for more convoys carrying humanitarian aid, medical supplies and fuel “to all areas of Gaza without exception,” the militia explained in a statement.