New York police were investigating Sunday an assault on a man who was pummeled by suspects shouting “ISIS, ISIS,” leaving him with bruises on his head and face, authorities said. The 43-year-old man was attacked while walking with a 9-year-old girl in the Bronx borough of the city Friday around 5:30 p.m., according to the New York Police Department.

The man was punched several times in the head, knocked down and kicked, police said. The victim, whose name was not given, was treated for injuries at a hospital and released.

He had been wearing a shalwar kameez, a traditional South Asian outfit featuring a long tunic, the New York Times reported.

The attack comes amid increasing anxiety in the U.S. over the threat posed by the Islamic State group, aka either ISIL or ISIS, which has claimed responsibility for militant attacks around the world.

A Muslim couple inspired by the extremist group killed 14 people in San Bernardino, California, Dec. 2, just weeks after gunmen linked to the Islamic State group killed 130 people in Paris.

Nobody was immediately arrested in the New York assault, which is under investigation by the police department’s Hate Crime Task Force, the agency said in a statement Saturday.