Israel’s military warned residents of Beirut’s southern suburbs, long a stronghold of Lebanese militant group Hezbollah, of imminent strikes and told them to evacuate.

WHO chief Tedros Adhanom Ghebreyesus said the Jnah district included the Rafik Hariri University Hospital and Al Zahraa Hospital, with some 450 patients in intensive care.

“At this time, no alternative medical facilities are available to receive” the patients, he said in a statement.

The evacuation of the intensive care patients was “operationally unfeasible”, he said — and both facilities were operating at full capacity, including treating those wounded by Israeli strikes on Wednesday.

“I urge Israel to reverse this order and ensure the protection of all health facilities, health workers, patients and civilians,” he added.

Israel on Wednesday carried out its largest wave of strikes since the start of its war with Hezbollah on March 2, killing more than 300 people, according to Lebanese authorities.

While Israel regularly issues evacuation warnings before bombing Beirut’s southern suburbs, Thursday’s announcement also included the outskirts of Lebanon’s only international airport.

The Rafik Hariri hospital is Lebanon’s biggest public health facility.