All westbound lanes of Highway 401 have reopened at Highway 25 in Milton after being closed for hours Thursday because of a truck fire and diesel spill.

The fire happened around 7:45 a.m. Pictures shared on social media showed a truck engulfed in flames. Ontario Provincial Police said the truck was carrying cheese at the time.

Firefighters, paramedics and police were called to the scene. No injuries were reported.

The road reopened briefly around 11 a.m. to allow a backlog of vehicles to clear, but then closed again for repaving. The highway fully reopened around 3 p.m.

Motorists who were stuck in the backlog during the busy morning commute took to social media to express their frustration.

“We have been stuck here for over 1 hour!” Twitter user @LuluTTMark wrote around 8:30 a.m.

“Stay off the 401 west between Mississauga and Guelph line. I haven't seen a traffic jam like that in years. 13km of parked cars!” wrote @jdalgetty.

The cause of the fire has not yet been determined.

@Josh_F is on Twitter. Remember for instant breaking news follow @cp24 on Twitter.