LEXINGTON, MASS. >> Two people have been critically injured in a crash on Route 128 in Lexington caused by a vehicle traveling south in the northbound side of the highway.

State police say the crash occurred at about 4:30 a.m. Tuesday just before the exit to Route 3.

Two people were taken to hospitals in critical condition. No names or any other information about the victims was immediately released.

The reason one vehicle was on the wrong side of the highway is under investigation.

The crash was causing traffic backups on both sides of the highway.