Authorities are searching for the attacker who got into an argument with another man before punching him on busy Manhattan street Tuesday.

According to NY1News, the incident happened around 6:30 p.m. in the Hell’s Kitchen section of Manhattan.

Surveillance video shows the two men exchanging words before one man punches the other man in the face.

The victim fell to the ground after the single blow and hit his head on the pavement, which caused a serious head injury. He was transported to a local hospital and is listed in critical condition.

The New York Daily News noted that the attacker fled the scene immediately after landing the punch.

Police say the men appeared to be strangers before the assault and there has not been any word yet on what sparked the public altercation.

The assailant is a blonde-haired man in his 30s. He was dressed in a turquoise T-shirt, cut-off blue shorts and gray sneakers. If you recognize him you are asked to contact authorities.