Israel intensified its attacks on Gaza on Sunday, calling for civilians to flee south where it vowed aid would increase, as the Red Cross warned of "intolerable" suffering.

The United Nations warned thousands more civilians could die in Gaza as Israel declared the war had entered a "second stage," stepping up its ground operations inside the Hamas-run territory.

Israel unleashed a massive bombing campaign after Hamas gunmen stormed across the border on October 7, killing 1,400 people, mostly civilians, and seizing 230 hostages, according to Israeli officials.