A railway overpass in Lloydminster, Sask., has collapsed after it was torn off its mounts.

A tractor-trailer carrying a track hoe hit the bridge, which RCMP said had a clearance of 5.1 metres, at about 2:30 p.m. CT, causing the collapse.

"It's right down to the ground. I mean, it's completely collapsed," said Lloydminster Mayor Jeff Mulligan. "The structure is obstensibly in one piece, but the section that's overtop of what would be the west-bound side of the highway is completely collapsed."

The driver of the truck was unharmed.

The accident on the east side of the city has forced the closure of Highway 16 in Lloydminster, which straddles the Alberta-Saskatchewan border.

Traffic has been halted in both directions and is being rerouted around the city. CP Rail workers have been sent out to assess the damage. The company says it will maintain service in the area while necessary repairs are made.

Police say traffic could be rerouted for up to two days.