According to rescue workers, at least two people were killed when a tribune in a synagogue near Jerusalem collapsed.
It was a 40-year-old man and a twelve-year-old boy, said the Israeli rescue service Magen David Adom on Sunday evening.
167 people were injured in hospitals, including five seriously injured.
According to the police, the grandstand was overcrowded.
Investigations were therefore started.
The accident occurred in the Israeli settlement of Givat Zeev in the West Bank.
This is in the northwest of Jerusalem.
The Shavuot festival began on Sunday.
On this day pious Jews commemorate the supposed delivery of the Torah, the Jewish Bible, by God to Moses.
According to biblical tradition, it is said to have taken place on Mount Sinai.
This area is now again under Egyptian rule.
Shavuot is also a harvest holiday.
At the end of April there was a mass panic in northern Israel during a festival to mark the Jewish holiday of Lag Baomer.
More than 40 people died.