The head of the World Health Organization says the Gaza Strip's health system is "on its knees and collapsing."

WHO Director-General Tedros Adhanom Ghebreyesus made the remark on Sunday at the executive board's special session on the health situation in the enclave.

Tedros said that as more and more people move to a smaller area, overcrowding combined with other factors are "creating the ideal conditions for disease to spread." He said, "On average there is one shower unit for every 700 people and one toilet for every 150 people."

Tedros added, "Only 14 hospitals out of the original 36 are even partially functional."

The WHO chief also referred to last week's US veto of a United Nations Security Council resolution calling for an immediate humanitarian ceasefire in Gaza.

He described a ceasefire as the "only way to truly protect and promote the health of the people of Gaza." He said, "I deeply regret that the Security Council was unable to adopt a resolution on such a ceasefire last Friday."