Locals were shocked when they spotted two tourists having sex on a beach in Thailand.

A youngster and his friends spotted the couple romping on top of a concrete bench on the Krating Lai Beach in Pattaya at around 2 am on February 22.

Niwat, 18, said he called out to the couple but they appeared not to understand what he was saying - and carried on with the woman bouncing up and down on the man's lap.

The lad then took out his phone to record them as evidence before calling the police. However, the couple had already finished by the time officers arrived.

Niwat said: 'I was with five of my friends and we were just relaxing on the beach. We heard a screaming noise coming from a dimly lit area so we checked what was happening.

'I saw that it was a man and a woman having sex and shouted 'stop' to them about three or four times. I said it in Thai, and we were laughing a bit, so maybe they did not understand me.

'I decided to take out my phone to record them. I tried again to make noise to warn them, but they continued their intimate act until they finished before washing themselves in the sea.

'I was shocked by the incident and how boldly they behaved in public. I hope that other tourists don't do this and instead do it in their rooms.'

Officers from the nearby station said that there was no evidence left at the scene. They were unable to find the holidaymakers in the immediate vicinity.

Police Colonel Navin Thirawit said: 'The tourists have not yet been identified. If it becomes an issue, we will check the CCTV cameras to find them.

'We would like the area to be a safe destination for families, so this kind of behaviour is strongly discouraged.'

The officer said the pair could face a fine of up to 5,000 Baht (115GBP) each for alleged public indecency.

Former fishing village Pattaya became popular with American troops on 'rest and relaxation' breaks in the 1950s and 1960s when the U.S. military had bases in Thailand while fighting Communism in Vietnam. Rural families are said to have dressed their sons as women to cash in on the gold rush.

The handful of bars in the coastal town quickly grew and it is now the world's biggest sex holiday destination, with round-the-clock prostitution and drugs - a modern-day Sodom and Gomorrah rife with crime and debauchery.

Government chiefs have attempted to clean up the city but regular violence, depravity and claims of corruption continue to blight its reputation.