United Nations schools where some 20,000 displaced people in the north of Gaza were sheltering were bombed by Israeli forces on Thursday, killing at least 20 people, United Nations Relief and Works Agency for Palestine Refugees (UNRWA) said.

"These are official UNRWA schools where we shelter a number of displaced persons in the north of Gaza.

"These shelters are clearly notified, the locations are well-known, and we have thousands of people...