A man was slashed in the face as he stood on the subway platform at 110th Street and Lenox Avenue in Harlem early on Sunday, after getting into an argument with a woman he did not know, the police said.

The attack joined a spate of slashings in the subway and on the street in the past month that have put New York City on edge, particularly because several were seemingly random and unprovoked.

“New Yorkers have a right to be alarmed or concerned, particularly those riding the subways,” Police Commissioner William J. Bratton said when he was asked about the attacks in an interview with AM 970 The Answer on Sunday morning. He characterized the episodes as “isolated incidents” that did not appear to fit a pattern.

What set off the argument between the 27-year-old man and the woman on the No. 2 train platform was not known to the police, but at some point the woman summoned a second man, with whom she was familiar, to where the altercation was taking place. That second man attacked the man with whom the woman had been arguing, slashing his face.