Three Toronto men were killed and a young woman was injured when the car they were driving in crashed into the Joseph River north of Bracebridge on Thursday night.

The car hit a guard rail on the Joseph River bridge, crashed through trees and plunged into the water just before 7 p.m. ET, Ontario Provincial Police said

"The vehicle left the roadway and entered the Joseph River and, unfortunately, at the time, three people were … removed from the vehicle," OPP Const. Skeeter Kruger said.

Jim Sawkins, fire chief for the Township of Muskoka Lakes, told CBC News that the speed limit on the section of road where the accident happened is 80 km/h, but the car was travelling much faster.

"The vehicle had hit and peeled back about 30 feet [about nine metres] of guard rail, and had launched itself and snapped some pine trees off approximately 25 feet [about 7.6 metres] in the air," he said.

Sawkins said there were golf clubs in the car, and believes the group was likely heading back to one of the cottages in the area.

The victims were identified as Tyler Mulcahy and Cory Mintz, both 20, and 19-year-old Kourosh Totonchian.

The fourth person in the car, 19-year-old Nastasia Elzinga, also of Toronto, was treated for minor injuries and released.

Police are investigating, but there is no indication what caused the accident.

Autopsies will be performed Saturday at South Muskoka Memorial Hospital in Bracebridge.

With files from the Canadian Press