The UN Palestinian refugee agency UNRWA has said six staffers were killed after two airstrikes hit a school in central Gaza a day ago, marking what it said was the highest death toll among its staff in a single incident, Reuters reports.

“Among those killed was the manager of the UNRWA shelter and other team members providing assistance to displaced people,” UNRWA said on X.

“This school has been hit five times since the war began. It is home to around 12,000 displaced people, mainly women and children,” UNRWA added.

The Gaza government media office said the Israeli strike killed at least 18 people, including the UNRWA staff members.

UN Secretary-General Antonio Guterres told Reuters on Wednesday that a lack of accountability for the killing of United Nations staff and humanitarian aid workers in Gaza was “totally unacceptable”.