Police arrested three security guards for assaulting two foreign customers in a violent dispute over payment of a friend's bill at a Pattaya bar on Sunday evening.

The three guards were identified by police as Ball, 27, Tom, 36, and Ice, 24. They were charged after allegedly seriously injuring two foreign customers at the Helicopter pub on Soi 6 about 5pm.

Police said the three men confessed to the crime. Mr Ball said a foreign customer shoved and punched him first. His nose was broken and he needed six stitches, he said. He apologised, saying he and his colleagues had lost control and overreacted.

The brawl was recorded by onlookers using mobile phones. Videos showed a security guard was attacked first. The three guards fought back violently, repeatedly bashing the visitors and leaving one of them unconscious.

Samorn, a cashier at the bar, said the tourists arrived in a group of three. Two of them paid their bills but the other had kept moving from table to table and had left without paying his bill.

The two visitors were annoyed when the cashier told them to pay their missing friend's bill. Initially they refused to pay and Ms Samorn called in the security guards who patrol the street.

The two visitors paid the outstanding bill, 2,800 baht. One of them then shoved a security guard out of the way, and a brawl started.