A 19-year-old female straphanger was hit in the face by a man on an A train at Columbus Circle on Friday afternoon, cops said.
The attack is the latest in the rash of violent incidents on the city subway system this year — including a random double-murder spree on the A line last weekend.
Friday’s assault happened just after 12:41 p.m., according to cops.
It is unclear what sparked the attack, but a good Samaritan stepped in to prevent further violence and held the man until cops arrived, police said.
The attacker, whose name was not immediately released, resisted arrest and bit one of the officers on his arm as they cuffed him, cops said.
The suspect was taken to Mount Sinai Hospital for a psych evaluation, according to police.
The cop was treated at Mount Sinai for the bite, which broke the skin, and the woman was treated at Lenox Hill Hospital for bruises to the face.
Charges are pending.