UN aid workers in northern Gaza “cannot find food, water or medical help” after nearly three weeks of “non-stop” Israeli bombing, a senior UN official said on Tuesday, citing reports from staff on the ground.

Philippe Lazzarini, head of the UN agency for Palestinian refugees, outlined the appalling conditions UNRWA staff are working under in the north of the enclave, where hundreds of thousands of people face a dire humanitarian situation amid a renewed Israeli military offensive.

CNN previously reported that Palestinians fleeing Israeli military operations in northern Gaza were being shelled as they evacuated, according to local residents and footage provided to CNN documenting their journey.

Lazzarini repeated calls for a ceasefire, “even if only for a few hours, to allow safe humanitarian passage for families who want to leave the area for safer places.”