The situation in the Gaza Strip is spiraling out of control, the head of the UN health agency warned on Wednesday, following a blast at a hospital that killed hundreds of people.

"The situation in #Gaza is spiraling out of control," the head of the World Health Organization (WHO) Tedros Adhanom Ghebreyesus said on X, formerly Twitter. "We need violence on all sides to stop," he said.

"Every second we wait to get medical aid in, we lose lives," he added. "We need immediate access to start delivering life-saving supplies."