The accident took place in the Jewish settlement of Kivat Jeev on the occupied West Bank.
Video footage shows a crowded grandstand collapsing and people falling on top of each other.
According to the ambulance service, at least 60 people were injured and ten of them were critically injured.
The Israeli military says it is sending medical personnel and search and rescue services to the scene.
Army helicopters carry out casualties.
A police spokesman said 650 people had gathered at the Intensive Orthodox Synagogue for the start of the Jewish holiday. Shawd.
The synagogue must have been under reconstruction. Someone who was with him told the newspaper Harretz The synagogue reopened for the first time on Sunday.
Quad Jeeve Meyer said construction was advanced and dangerous, and police ignored calls for further action.
That was two weeks ago 45 people lost their lives In a similar accident in northern Israel.
The news agency writes that the accident led to criticism of the widespread self-government of radical Orthodox Jews.
Last year, several coronary restrictions were violated in the area, which led to outbursts among extremist Orthodox and criticism from the secular population.