In a statement, Volker Turk said he was appalled by Monday's deadly strike which reportedly killed at least 18 people, including four children, and reiterated that the fundamental principles of international humanitarian law concerning the protection of civilians must be respected.
He noted that the hospital, one of the main medical facilities in Beirut, which has received a large number of patients throughout the conflict, also appears to have been damaged in the strike.
"In the conduct of military operations, all feasible precautions must be taken to avoid, and in any event to minimize, incidental loss of civilian life, injury to civilians and damage to civilian objects," Turk underlined.
He said that hospitals, ambulances and medical personnel are specifically protected under international humanitarian law because of their lifesaving function for the wounded and the sick.
"When conducting military operations in the vicinity of hospitals, parties to the conflict must assess the expected impact on health care services in relation to the principles of proportionality and precautions.
"Any incidents which affect hospitals must be subjected to a prompt and thorough investigation,” he added.
Turk also recalled the UN’s call for an immediate cessation to hostilities and reminded all parties that the protection of civilians must be the absolute top priority.
Israel has mounted a huge air campaign in Lebanon since Sept. 23 against what it says are Hezbollah targets in an escalation from a year of cross-border warfare between Israeli forces and the Lebanese group since the start of Israel’s brutal offensive on Gaza.
Nearly 2,500 people have been killed and more than 11,500 others injured in Israeli attacks since last year, according to Lebanese health authorities.
Israel expanded the conflict on Oct. 1 this year by launching a ground assault into southern Lebanon.