Speed is believed to have been a factor in a fiery collision that injured four people and closed a large stretch of the Gardiner Expressway Thursday night, Toronto police say.

Emergency crews were called to the eastbound lanes of the highway near Fort York Boulevard just before 7:30 p.m. for a multi-vehicle crash.

Police initially said that two drivers of Mercedes-Benz vehicles with Quebec licence plates “were racing” when they collided. Two other vehicles were also involved, police said.

Traffic Services later clarified that they do not believe that the vehicles were racing, but speed was likely a factor in the collision.

One of the vehicles caught fire as a result of the collision, police said. Video taken by a motorist travelling on the highway and shared with CP24 shows large flames and thick black smoke billowing from the vehicle.

Police said four people were transported to the hospital with minor injuries.

Meanwhile, two occupants of one of the Mercedes vehicles fled the scene on foot. One of them is still outstanding.

All eastbound lanes of the highway beyond Jameson Avenue were closed for about two hours, causing heavy traffic.