SAN FRANCISCO, Sept 19: Michigan state police are investigating an assault on four Pakistani doctors by three men at a golf club, press reports said. One of the doctors was injured seriously and taken to a hospital.

An altercation began when the doctors had finished up on the 18th hole and one of the attackers hit a ball onto the green without warning, a victim said.

Three of the Pakistanis were preparing to leave in the parking lot when one of the attackers pulled up in a golf cart and began to curse them. The victim said the attacker did not use racial slurs but threatened to punch the doctors in the face.

One of the Pakistanis went into the clubhouse to call police. An attacker grabbed a doctor and asked him where the key to his golf cart was, the victim said.

When the doctor told the man he didn't know about the key another man walked up and struck him in the face - knocking him unconscious. When he gained consciousness he saw one of the other doctors on the ground with blood on his face. He had to undergo reconstructive surgery, police said.