A car plunged into Lake Ontario in Toronto’s Port Lands Thursday afternoon, possibly with a motorist inside but rescue crews said nightfall has forced them to suspend their recovery efforts until morning.

Rescue crews rushed to the scene on the Cherry Street bridge, just south of Polson Street, shortly before 4 p.m. after witnesses called 911 to report a car in the water.

By 6:30 p.m., Sgt. Brett Moore said divers had located the car but still could not confirm if anyone was inside. The darkness forced them to abandon their efforts.

Witnesses told police the vehicle was speeding north on Cherry Street when it crossed the median, drove over the sidewalk on the bridge where it broke through the railing and plunged into the water below.

They said the car quickly became fully submerged in the lake. The lake is believed to be more than 25 feet deep.

"We're suspecting that there was a driver in the vehicle," Toronto Fire Platoon Chief Kevin Aucoin told reporters at the scene.

Aucoin said that a passerby on a bicycle attempted to dive into the water and locate a driver. He said that the civilian has since been rescued from the water and transported to hospital to be treated for hypothermia.

"There were witnesses on scene that saw it go in so we're going by what witnesses said on our arrival," he said.

Firefighters and police in dinghies and other boats searched the water beneath the bridge until the rescue efforts were suspended for the evening.

Cherry Street will remained closed to traffic overnight.