A 13-year-old boy was injured while subway surfing on an F train on Tuesday afternoon, police say.

The boy, who reportedly got on the train at the Avenue U station, was riding outside of the southbound train when was injured at the Neptune Avenue station. DNAinfo reports the unnamed teen "managed to ride the length of the platform before striking the 'Do Not Enter' sign at 5 p.m.," according to an NYPD spokesperson.

The boy fell into the tracks and was taken to Maimonides Medical Center in serious condition. A police source told the Daily News the teen sustained cuts to his face, multiple bruises to his stomach, and ruptured testicles.