An Israeli military raid targeting Hamas militants has forced a major hospital in northern Gaza out of service and led to the detention of its director, the WHO and health officials said on Saturday.

The assault on Kamal Adwan Hospital has rendered the facility "useless", further worsening Gaza's severe health crisis, the Palestinian territory's health officials said.

The World Health Organisation said the operation had put the "last major health facility in north Gaza out of service."

"Initial reports indicate that some key departments were severely burnt and destroyed during the raid," it added in a statement on X.

The WHO said 60 health workers and 25 patients in critical condition, including some on ventilators, reportedly remained in the hospital.

Patients in moderate to severe condition were forced to evacuate to the destroyed, non-functioning Indonesian Hospital, the UN health agency said, adding it was "deeply concerned for their safety."

Hamas-run Gaza's health ministry reported that Israeli forces had detained Kamal Adwan's director, Hossam Abu Safiyeh, along with several medical staff members.

Gaza's civil defence agency said Abu Safiyeh was held alongside its north Gaza chief, Ahmed Hassan al-Kahlout.

The Israeli military did not comment on the detentions. (AFP)