The strikes constitute a "dangerous escalation which threatens to bring serious consequences for the stability of the region", said the statement from Egypt, which brokered the Gaza ceasefire alongside Qatar and the United States.

It called on the international community to "act immediately to halt the Israeli aggression against the Gaza Strip in order to prevent the region entering a new spiral of violence and counterviolence".

Israel's overnight strikes, which the health ministry in Hamas-run Gaza said killed more than 400 people, were by far the biggest since the ceasefire. Hamas has not responded militarily so far.

Jordan, which like Egypt neighbours Israel, also condemned the strikes.

"We have been following since last night Israel's aggressive and barbaric bombing of the Gaza Strip," government spokesman Mohammed Momani said, underlining "the need to stop this aggression".

US President Donald Trump has floated a proposal to move Gaza's population out of the war-battered territory, suggesting that Egypt or Jordan could take them in.

Both countries, along with other Arab allies, governments around the world and the Palestinians themselves, have flatly rejected the notion.

Arab nations have since come up with an alternative plan for rebuilding the Gaza Strip without relocating its people.

burs/ser/smw