U.S. Secretary of State Antony Blinken, in his strongest public criticism of Israel's conduct of the war on Hamas in south Gaza, said there was a gap between the government's declared intentions to protect civilians and the casualties.

"As we stand here almost a week into this campaign into the south ... it remains imperative that Israel put a premium on civilian protection," Blinken told a news conference after meeting British Foreign Secretary David Cameron in Washington on Thursday.

"And there does remain a gap between ... the intent to protect civilians and the actual results that we're seeing on the ground."