A man was stabbed early Monday in a group attack at a Manhattan subway station, police said.

The 21-year-old was on the northbound platform at the 96th Street B/C station on the Upper West Side at 1:45 a.m. when he was stabbed in the torso with an unknown object, cops said.

A group of men believed to be responsible for the attack fled on foot, according to police.

The victim was taken to St. Luke’s Hospital in serious condition, FDNY officials said.

Trains bypassed the 96th Street station in both directions while police conducted an investigation, the MTA tweeted.