A man was rushed to hospital with life-threatening head injuries after a severe beating on James Street North Sunday afternoon.

Witnesses say the man left a bar on the street about 2:30 p.m. with two other men.

"He was really drunk and was antagonizing them," said Ken Blackburn, who watched the entire incident. "He didn't even have shoes on he was so drunk."

Blackburn told CBC Hamilton that one of the men took off and the other two started yelling and trading punches in the street.

"The bigger of the two guys kept saying 'I just got out of the pen, I'm going to knock you out.' Then he kicked him in the leg, knocked him down and just jumped on him," Blackburn said.

The man then repeatedly punched the other man and stomped his head into the ground, Blackburn says.

About 40 people saw the incident happen, says Sherelle Wilsacka, who was in the James North Art Collective just across the street.

"They were fighting right in the middle of the street, stopping traffic," Wilsacka said. "I went out into the street and told him to stop it, and he just said 'you want a piece of this?'"

"Everyone was yelling at him to stop. There was a lot of blood," she said.

Blackburn says at this point, someone came out of a café and told the man they had to leave.

"They got into a car, drove down Barton and took off," he said. "Three or four people took pictures of the car and the plate."

Police and paramedics arrived soon after, he said. According to Hamilton EMS, the man was taken to hospital with life threatening head injuries.

Hamilton police say the incident is being treated as an assault, and they are investigating.

The area around James Street North and Murray Street was closed and cordoned off with yellow tape Sunday afternoon as officers gathered evidence and interviewed witnesses.

Residents staying at the Mission Services of Hamilton said the injured man had been staying there, but staff said they could not confirm or deny if he was.

"I feel really sorry for the guy," said Mark, who is staying at the Mission Services and did not want his last name used. "He was on the ground breathing hard like his lungs were collapsing. It was awful to see that."

Police describe the assailant as white, around six foot two inches tall, and about 220 to 240 pounds. He is said to be balding, with a tattoo of a cross or crown on his neck and was last seen wearing red basketball shorts.

The car he got into is described as a black, four door, older model Honda.

Anyone with information is asked to call Crime Stoppers at 905-522-8477.