ST. LOUIS, Mo. -- A police officer was shot in south St. Louis Sunday night.

The shooting occurred at the intersection of Hampton and Pernod Ave just before 7:30 p.m.

Speaking to the media, St. Louis Police Chief Sam Dotson said the officer, a 20-year veteran of the force, was ambushed by an individual who shot out the police officer's window. The officer was shot twice in the face.

The officer then called for assistance following the shooting. He is currently listed in critical, but stable condition.

The suspect is still on the loose.

Dotson said St. Louis city officers will have two officers per squad car for the time being.

CrimeStoppers announced a reward of up to $5,000 for information that leads to the arrest of the person who shot the officer twice in the face.

Call 1-866-TIPS (8477) if you have any information that may help authorities.

As more information becomes available, this story will be updated.

Photos: Scene photos of officer shot in south St. Louis.