Authorities said a wrong-way driver crashed head-on into an off-duty Milwaukee police officer who was on his way home.

The Milwaukee Police Department said the 31-year-old officer had just gotten off work when he was hit and critically injured.

The crash happened early Wednesday on Interstate 94. The Milwaukee County Sheriff's Office said 23-year-old Erin Salmon of Milwaukee was driving westbound in the eastbound lanes.

Both drivers were trapped in their cars. The Milwaukee Journal Sentinel reported they were freed and taken to a hospital in critical condition.

The Sheriff's Office said Salmon was issued citations for operating while intoxicated-first offense; driving the wrong way on a divided highway; driving without proper lamps lighted; and reckless driving/endangering safety.

The crash shut down eastbound I-94 for four hours.