An American veteran was left covered in blood in an alleged attack by a Thai local.

Radford Lee Mays, 82, was out on his nightly jog around a public park when an allegedly drunk Thai man reportedly assaulted him unprovoked in Pattaya, Thailand, on September 4 evening.

The confused pensioner escaped and sought help from residents, who then called medics to give him first aid.

Footage shows the shirtless expat covered in blood from a gruesome wound on his left eyebrow.

Officers said he was 'in a fearful state' as they questioned him through an interpreter.

Radford said he regularly exercised at the park without problems. He added that he had never met the Thai man, believed to be in his 30s, who allegedly attacked him.

The American said: 'He attacked me before I had a chance to defend myself. I am in good shape but it was too fast for me. I'm a bit shaken up by what happened.'

Security guard Surachai Kaenthongcharoen, 45, said he was on a patrol around the park when a villager approached and told him Radford had been injured.

He said: 'I saw a tall, drunk Thai man who was screaming at the tourist and claiming that he was from Pattaya. I called volunteers and the police, but he fled before they arrived.'

A Pattaya Police Station spokesman said cops tried to intercept the Thai man but were unable to catch him along his escape route.

He said: 'Investigators will continue to inspect the area to search for clues to track down the suspect and proceed with legal action.'

Former fishing village Pattaya became popular with American troops on 'rest and relaxation' breaks in the 1960s when the U.S. military had bases in Thailand. In the ensuing years, the coastal resort spawned into notorious sex destination.

Embarrassed officials have made progress in gentrifying the region with family tourism projects but a ravenous nightlife industry and corrupt police have hampered their efforts, with undesirables from all nations still attracted to the seedy city.