An American man caught recording a Thai military airport was arrested over fears he was spying for Cambodia.

Joshua Brian Wolak, 46, from New Jersey, was using his smartphone to capture shots of army base in Surin province, Thailand, on December 16. It is unusual for any holidaymakers to visit the remote region, particularly during times of conflict.

The tourist sparked alarm when border patrol police and joggers saw him 'loitering suspiciously' in the area while wearing a green military-style cap and black Ray-Ban sunglasses.

Upon noticing he was being watched, he was said to have fled into a public toilet, where he remained until officers arrested him.

Footage shows the tourist gesturing 'I don't know' as he was questioned by police. He refused to have his phone inspected, prompting them to take him to the station for further interrogation.

Officials released him later in the evening as they failed to find evidence of espionage.

Police Colonel Ekkaphong Phonmanee, superintendent of Mueang Surin Police Station, said today: 'Yesterday, we interrogated him and held a meeting with security agencies.

‘At around 7 pm, we released him. The investigation found no evidence of espionage or any threat to national security, so we released him.

‘There were no suspicious images on his phone, and the photos he took did not show any strategic locations.

‘During questioning, he insisted that he was in Thailand for tourism.'

Police added that Joshua had checked into a hotel in Surin on December 15. He was in Thailand alone on a holiday.

The arrest comes after police warned residents in northeast Thailand to monitor Russian tourists, following reports that the Cambodian army had enlisted foreign agents to operate in the region.

Territorial clashes flared up earlier this year before a brief ceasefire, but started again this month when Cambodian troops are said to have fired on a Thai engineering team building an access road in a disputed border area.

In the most recent battles, at least 21 Thai soldiers and one civilian have been killed. In Cambodia, the number of military fatalities is believed to be much higher, though regime chiefs have not revealed the actual figure.

Around 600,000 people have been displaced on both sides of the border.

Cambodia's assault has largely been wayward, unguided rockets fired indiscriminately into Thai territory, including an attack on July 24 that killed eight people and injured 13 others. Thailand has used precision drone strikes and fighter jet strikes on military sites.

Former Khmer Rouge henchman and Cambodian dictator Hun Sen has repeatedly claimed that he wants peace and that Thailand is the aggressor.

Thai officials claim the ongoing border confrontations are a threat to national security, and the areas must be secured.