Thousands of Palestinians have continued to leave northern Gaza and cram into already crowded schools, homes and makeshift shelters in the south, as Israeli airstrikes pound the blockaded strip ahead of an expected ground invasion.

Foreign citizens may be allowed to leave the enclave on Saturday under a deal agreed by Egypt, Israel and the United States, senior Egyptian and US officials said.

About 2.3 million Palestinians are trapped in Gaza, facing a terrifying escalation of bloodshed and misery, after Israel sealed all crossings into its territory and Egypt reinforced it border crossing, saying it would not allow refugees to enter.

Food, fuel and water supplies were dwindling fast on Saturday after Israel cut all movement in and out of Gaza. The death toll from airstrikes, already at unprecedented levels, had reached more than 2,200. That included 724 children and 458 women, the Gaza health ministry said.