A 12-year-old boy is among two people who have died after a seating structure collapsed at a synagogue in Israel.

More than 150 people have been injured as ultra-Orthodox worshippers packed into the West Bank synagogue to celebrate the beginning of a major Jewish holiday on Sunday evening.

A man in his 50s was also killed in the incident in Givat Zeev.

Amateur footage shows the tiered seating structure collapsing during prayers, sending worshippers plunging to the ground.

Medics and search and rescue teams were sent to the incident and some of those injured were airlifted to hospital by army helicopters.

Officials have said the five-storey building was incomplete and dangerous, with videos from the scene showing exposed concrete and plastic sheeting used as windows.

The mayor of Givat Zeev said police had ignored previous calls to take action on the unfinished building.

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Jerusalem police chief Doron Turgeman said the disaster was the result of “negligence”, adding there would likely be arrests.

Deddi Simhi, head of the Israel Fire and Rescue service, told Israel’s Channel 12: “This building is not finished. It doesn’t even have a permit for occupancy, and therefore let alone holding events in it.”

A sign has now been pasted onto the wall of the building warning that “for safety reasons entrance to the site is forbidden”.

Worshippers had been celebrating Shavuot, a spring harvest festival that also marks the day in the Jewish calendar that the Torah was given to Moses on Mount Sinai.

The disaster happened just weeks after a stampede at a religious festival in northern Israel killed 45 ultra-Orthodox Jews.

The stampede at Mount Meron was the deadliest civilian disaster in the country’s history.