Dozens of people were killed in a crush at a religious bonfire festival in Israel on Friday, medics said, in what Prime Minister Benjamin Netanyahu has described as a "heavy disaster."

Tens of thousands of ultra-Orthodox Jews had gathered at the Mount Meron tomb of the 2nd-century sage Rabbi Shimon Bar Yochai for annual Lag B'Omer commemorations, which include all-night prayer and dance.

The ecstatic crowds congregated despite warnings by health officials to avoid presenting COVID-19 risks. Witnesses said they realized people had been asphyxiated or trampled when an organizer appealed over a loudhailer for the throng to disperse.