Video footage of a 67-year-old white man hitting a young black man on a bus has sparked a race row in the U.S after it became an internet sensation.
The fight, which was filmed by a college student who was on the bus in Oakland, California, appears to have been started by racist comments.
The student said the row erupted after the elderly white man made a remark about shoe-shining.
The video shows the 67 year old - known on the web as Epic Beard Man - punching the black man after a seemingly racially-charged slanging match breaks out between them.
'The white guy was asking the black guy for a shoe-shine,' Iyanna Washington, the student who shot the video with a small camera, told CBS station KPIX.
'And I guess the black guy took it as a racist comment, like, "Why's a black guy have to spit shine your shoes?"' she said.
Despite the racial overtones, the older man at one point insists: 'I ain't prejudiced.'
After arguing for a short while, the older man, who wears a T-shirt that reads 'I'm a motherf*****', gets up and moves to the front of the bus.
The younger man follows him, while other passengers on the bus attempt to break the row up.
One woman can be heard saying, 'It ain't worth it'.
It appears the black man throws the first punch, but he is left bloodied after the 67-year-old unleashes a flurry of punches to his face.
The younger man was later found to have sustained a broken nose, Clarence Johnson, a spokesman for the bus company said.
The older man can be seen leaving the bus but remains in the area, screaming and kicking at a newsstand. He eventually surrendered when police arrived.
Both men were taken to the hospital. Miss Johnson said the older man hadn't been taking his medication.
It is not clear what he was taking medication for.
The video has polarised opinions about race in the U.S., and despite the election of America's first black president, it seems the issue of race still deeply divides the country.
Several racist comments have been posted after the video appeared on YouTube.
One wrote: 'You don't mess with Epic Beard Guy!!! he really rulz, dumb n***** tried to mess with him so he got his face pwned
'
Another claimed the row was not racially motivated: 'That black dude was an a**hole and got what he deserved...no racism involved...except if you consider the black guy trying to pull the race card in a fight with the 67 year old dude.'
Another wrote: 'he was p*****. He's not f***** up. The n***** got what was coming.
'The n***** antagonized him until the dude's adrenaline started flowing and fortunately to those two n******...he was still able to control himself when his adrenaline kicked in.'
The video has had around 700,000 hits on YouTube, although many more will have seen the row after several blogs picked it up.
The woman who filmed the fight has also been accused of stealing the older man's bag, although she denies this and has posted her own video on YouTube to refute the allegations.
Several spoof versions of the bus fight have now appeared online, including one where the 67-year-old has been turned into a character from the video game Mortal Kombat.
The event even has its own Wikipedia entry.
