A video posted on social media appears to have been the catalyst for a west-end Toronto shootout between two groups this week — with cops caught in the crossfire, a police source says.

Undercover officers were in the area of Queen Street W. and Sudbury Street on Monday night, conducting a bail compliance check, Police Chief Myron Demkiw said Tuesday.

A police source, who CBC News is not identifying because they are not authorized to speak publicly about the investigation, said undercover officers from 52 Division were at an address in the area looking for a wanted person who was partying with a group of people.

Someone posted about that gathering on social media, the source said, which led to another group showing up and taking cover behind an unmarked police car with officers inside.

There was an exchange of gunfire between the two groups, and the police vehicle was struck with bullets. No one was injured.

Twenty-three people were arrested at the scene and several firearms were recovered, investigators say.

Toronto police are expected to reveal more details about the investigation Thursday.