Israel has delayed an expected release of hundreds of Palestinian prisoners and detainees in exchange for returned Israeli hostages “until further notice,” the Palestinian Prisoners Society said early Sunday.

The hostages are the last living hostages to be freed in the first phase of a fragile deal with Israel, adding to pressure for both sides to start negotiations to permanently end the war.

Israeli hostages Avera Mengistu and Tal Shoham were released in Rafah. Four more hostages are set to be released Saturday in the largest swap under January’s ceasefire agreement.

Gazans gathered in large numbers to show support for the Ezzedine al-Qassam Brigades, Hamas's armed wing, as Israeli hostages were handed over to the Red Cross in Rafah. The exchange has intensified emotions in the region,