Cambodian and Thai soldiers exchanged artillery and small arms fire near the Preah Vihear temple complex along a disputed stretch of their shared border on Friday, Cambodian and Thai military sources said on Friday.

The fighting began just after 3pm and remained ongoing as of early Friday evening, according to a Cambodian soldier stationed in the area, who asked not to be named because he was not authorised to speak to the press.

A Thai regional commander in the area, Lieutenant General Thawatchai Samutsakorn, said there was “sporadic shelling but details are very sketchy at this point”.

Cambodian police told Reuters that two Cambodia soldiers were killed and two others injured in the clashes, the latest deaths in the area since a Thai soldier was shot and killed on January 31 last year.

Thai army spokesman Sansern Kaewkamnerd said late Friday that five Thai soldiers had been captured by Cambodian forces, while Thai media reports said three our four Thai soldiers had also been injured.

Cambodian Foreign Minister Hor Namhong told reporters at Siem Reap airport prior to his departure for Phnom Penh that the Cambodian government would file a formal complaint against Thailand with the United Nations.

Foreign Ministry spokesman Koy Kuong said Friday afternoon that Hor Namhong and his Thai counterpart, Kasit Piromya, attended a meeting of the Joint Commission for Bilateral Cooperation this morning in Siem Reap, but that recent tensions along the border were not discussed.

“We are always prepared to protect our sovereignty. Shooting is just for self-defense and the protection of our land,” he said.

The hostilities follow the sentencing Tuesday of Veera Somkwamkid, a well-known activist within Thailand’s nationalist Yellow Shirt movement, and his associate, Ratree Pipatanapaiboon, to eight- and six-year prison terms respectively.

Veera and Ratree were convicted by the Phnom Penh Municipal Court of espionage, illegal entry and unlawfully entering a military base after being arrested in Banteay Meanchey province last month.

The fighting also comes amid a public spat with Thai Prime Minister Ahbisit Vejjajiva over the placement of Cambodian flags at Wat Keo Sekha Kirisvara, a pagoda adjacent to the Preah Vihear temple.

Yim Phim, commander of Royal Cambodian Armed Forces Brigage 43 in Preah Vihear, said yesterday that troops on both sides of the border had received reinforcements and additional equipment this week.

Minister of Information Khieu Kanharith, government spokesman Phay Siphan and Srey Doek, commander of the Royal Cambodian Armed Forces Military Division 3 at the border were unavailable for comment on Friday.

Periodic skirmishes between Cambodian and Thai border forces have killed at least seven soldiers since 2008.

Additional reporting by Reuters