GAZA -- The Al-Qassam Brigades, the military wing of the Palestinian Islamic Resistance Movement (Hamas), announced Saturday in a statement that it had decided to delay the release of the second batch of Israeli hostages, blaming Israel for failing to meet the terms in a four-day humanitarian cease-fire agreement.

The delay was due to Israel's failure to comply with the terms in the agreement regarding the entry of relief trucks into the northern regions of the Gaza Strip and the agreed-upon criteria for releasing prisoners, according to the statement.

The second exchange of Israeli hostages for Palestinian prisoners was scheduled to take place around 4 pm local time (1400 GMT) Saturday but was delayed for several hours.

A Palestinian source told Xinhua that Hamas was expecting the delivery of "large quantities" of humanitarian aid to Gaza City and the rest of the northern part of the Gaza Strip, rather than providing supplies to the southern part of the enclave only.

Hamas also demands that the Palestinian prisoners to be released by Israel should include those from the Gaza Strip, said the source.

Taher al-Nono, an advisor to Hamas leader Ismail Haniyeh, said Israel had breached the agreement, particularly with regard to the entry of humanitarian aid trucks.

An Israeli official threatened that if the second group of Israeli hostages is not released by Hamas before midnight, the Israeli army will "restart ground operations" in the Gaza Strip, Israeli media outlets have reported, without providing further details.

Under the mediation by Qatar and Egypt, Hamas and Israel on Wednesday agreed to a four-day humanitarian cease-fire to force a temporary halt to the fighting between the two sides. After the truce deal went into effect Friday, Hamas released 24 hostages, including 13 Israelis, 10 Thai, and one Filipino, while Israel freed 39 Palestinian prisoners. The release of non-Israeli nationals was not part of the truce deal.