Toronto police say they are investigating after receiving a complaint about a music video that the city's transit authority says takes aim at its workers.

A spokesman for the Toronto Transit Commission says the agency complained about the rap video posted online, saying it "threatens extreme violence against TTC employees."

Brad Ross says the TTC takes issue with "the threat of violence stated in the lyrics and the mimicked actions of discharging a firearm."

The video, by an artist called 6ixreacts, appears to be filmed on subways and at subway stations in Toronto.

Ross says the people in the video didn't seek permission to film on TTC property, and if they had asked, they would have been denied due to the nature of the song.

The artist says he made an "innocent" video.