Paul Browne, a man who was suspected of groping a teenage girl and another woman in a subway station was shot in buttocks by an off-duty officer on the train platform when he tried to run away.

The incident happened in Harlem, New York, at the 125th Street station in front of dozens of horrified passengers.

According to police, the mother of a teenage girl yelled for officers at about 12:30 p.m. in the station.

The off-duty transit officer, who happened to be nearby, came to the woman’s aid.

Another woman also told the officer she was groped by the same man, nbcnewyork.com reports.

The mother called 911 from a pay phone inside the train station after the officer told her to call for backup.

There were shouts of “police – get down” before one shot was fired, witnesses said.

Paul Browne was hit once in the buttocks and was in a stable condition in hospital Friday afternoon.

Witness Orbit Clanton said: “He had the suspect face down, facing north. And when the trains entered the station, what happened was the suspect tried in an aggressive move to get up.”

Police said that in the preliminary stages of their investigation it was unclear whether the officer fired the gun or if it went off in the struggle with the suspect.

A knife was found on the tracks nearby but it was not clear whether the knife was part of the interaction between the officer and Paul Browne, the department’s chief spokesman, said.

The incident resulted in delays on four subway lines afterwards.

There were residual subway delays Friday evening along the A, B, C and D lines.