Police have released a sketch of a man wanted in connection with a criminal sex act that they said took place on an F train.

A 27-year-old woman was riding the southbound train in Brooklyn at 2:15 a.m. Thursday when she fell asleep, the NYPD said. She awoke to find a man rubbing himself against her, police said.

The suspect, about 20 years old, is described as 5-feet-11 and 160 pounds, with brown eyes and brown hair. Police said he was last seen wearing a green jacket, a dark-colored hoodie and jeans.

He fled at the Neptune Avenue station, police said.

Anyone with information is urged to call NYPD Crime Stoppers at 800-557-8477.