MONTICELLO, Minn. — The Minnesota State Patrol is investigating a multi-vehicle crash on Interstate 94 near Monticello.

The agency said the crash occurred around 9:15 a.m. Thursday on the interstate near Wright County Road 18. The crash involved 29 vehicles, half of which were semi-trailers.

Several vehicles caught fire and nine people were transported to a hospital with what appeared to be minor injuries. The State Patrol is searching for several drivers who left the scene before first responders arrived.

The crash closed the interstate for several hours. Eastbound lanes had reopened but westbound lanes were still closed as of 2 p.m.

The State Patrol said poor visibility and slippery conditions due to a snow squall had made travel "extremely difficult" in the area when the crash occurred.

The State Patrol released photos of the scene that showed burned-out hulks of cars, debris scattered across the pavement and smoke from burning semi-trailers billowing into the sky.