Startling video shows a group of teens hurl a metal pole through a Brooklyn synagogue window while congregation members were observing the Sabbath inside.

The footage released by Williamsburg Shomrim on Twitter on Sunday shows half a dozen teens loitering near the synagogue on Franklin Avenue near Myrtle Avenue around 5:45 p.m. Saturday, according to the tweet.

The kids are seen leaning against a wrought-iron fence talking to each other while one of the teens — wearing dark clothes and a white, patterned backpack — is carrying the metal pole, the video shows.

Suddenly, the boy hands the pole to a friend wearing a bright orange top — who launches the metal bar into a ground-level window, leaving a gaping hole.

“People were praying inside at the time,” said a man who was at the temple during the incident.

The building includes a predominantly Hasidic apartment complex above the first-floor synagogue.

The group then took off, running south on Franklin Avenue. No one was injured in the attack.

Police said Monday they are investigating the incident as a hate crime.