Prabhjot Singh is a professor at the School of International and Public Affairs at Columbia University

A Sikh professor at Columbia University was allegedly attacked by a group of men in an assault which the police are investigating as a hate crime.School of International and Public Affairs professor Prabhjot Singh was assaulted on Saturday night while walking in the Harlem neighbourhood near New York.In an online post, Mr Singh's friend Simran Jeet Singh, who is a doctoral candidate in religion at Columbia, said Mr Singh had been "brutally attacked" on the street and had been rushed to the hospital "bloody and bruised, his face swollen from a fractured jaw."The young professor could not speak because his teeth had been displaced, Jeet Singh said in the post 'Hate Hits Home: When My Friend Became A Target' published on the HuffPost website."Last night, I received the kind of phone call that everyone dreads: a close friend was hurt, and on his way to the hospital. But the news got worse, as I learned that my friend, Dr. Prabhjot Singh, a young Sikh American professor at Columbia University, had been brutally attacked on a public street, the victim of a violent hate crime," the post said.While in hospital, Mr Singh communicated to the police that his assailants taunted him and beat him, calling him "Osama" and "terrorist" as they pulled at his long beard. He was repeatedly punched in the face and head as he lay on the sidewalk.Mr Singh had returned from dinner and after dropping his wife and one-year-old son at home, had gone for a walk.Mr Singh was unable to provide any descriptions about his assailants.Jeet Singh described the young professor as someone who has "dedicated his life to serving the underserved."Mr Singh is also a resident physician at a leading New York hospital. "Unfortunately his assailants did not see Prabhjot Singh, the professor, the community health expert or the local doctor. They saw a man wearing a beard and a turban - his articles of faith - and saw a target. Sadly, for many other Sikh Americans like Prabhjot, this is a story they have heard and experienced before," Jeet Singh said in his online post.Mr Singh has been discharged from hospital and had met with officials from the New York Police Department Hate Crime Task Force, who are investigating the incident as a hate crime.Following the attack on Mr Singh, the New York chapter of the civil rights group Council on American-Islamic Relations (CAIR) called on state political and religious leaders to speak out against bias-motivated crimes.

"New York's religious and political leaders must speak out forcefully against the type of bigotry that leads to hate attacks on people of all faiths and backgrounds," said CAIR-NY Operations Coordinator Sadyia Khalique in a statement.