Updated

The United Nations kept its aid deliveries to the Gaza Strip on hold Friday as Israel and Hamas ignored a Security Council cease-fire demand.

Palestinians who risked going to Gaza relief centers, however, could still receive food and medicine.

The U.N. Relief and Works Agency suspended relief shipments to Gaza on Thursday, after Israeli strikes killed two agency drivers and injured a third — all in clearly marked U.N. vehicles, officials said.

U.N. spokeswoman Marie Heuze said Friday that aid deliveries would resume after a cease-fire comes into effect in Gaza, as demanded by the Security Council in New York on Thursday night.

But Israel pressed forward Friday with its offensive against militants from the Islamic group Hamas, and Hamas responded with a barrage of rockets. Both sides said they would ignore the call to lay down their arms and end 14 days of fighting that has killed nearly 760 Palestinians and 13 Israelis.

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U.N. relief agency spokeswoman Elena Mancusi Materi said U.N. trucks would begin moving aid around Gaza again only after Israel promised not to shoot at the vehicles. The agency and the Palestinian truck company it contracts would have to be convinced by an Israeli security guarantee, she said.

The World Food Program and UNICEF said they also were not moving supplies into or around Gaza.

But agencies said they were still operating in the Palestinian territory, where 1 million people are without electricity and 750,000 are without running water, according to the U.N. relief agency.

The World Food Program can access 1,900 metric tons of food it already has in Gaza — enough to feed over 130,000 people into February, spokeswoman Emilia Cassell said. But the agency needs 130 more truckloads of food delivered to ensure supplies beyond then, she said.

She said the World Food Program had provided regular rations to 60,000 people and fed at least 20,000 more since Israel launched its attacks Dec. 27 — aimed at halting rocket fire from the Hamas-controlled territory.

Cassell said the agency would continue feeding those who can reach food distribution centers in the Gaza Strip until security improves enough for trucks to resume moving supplies around.

The Jewish state has been severely criticized by the international Red Cross and the United Nations for preventing humanitarian groups from caring for wounded civilians and for firing on aid convoys.

Israel's Mission to U.N. offices in Geneva said in a statement that it recognized the importance of the work of international aid groups in Gaza "during this period of hardship to the local population due to the ongoing fighting."

The statement said Israel was doing everything it could to help, citing the three-hour pauses in fighting it agreed to during the last two days to facilitate humanitarian work.

The International Committee of the Red Cross said it is currently restricting operations to Gaza City after one of its drivers was injured by fire from an Israeli post south of the city. The group hopes to return to the field Saturday to pick up injured people and repair water supply systems, spokeswoman Anne Sophie Bonefeld said in Jerusalem.