The tense stand-off at the Preah Vihear temple on the Cambodian-Thai border escalated into the most serious fighting between the two countries yet in early February. Thousands of civilians were displaced and an uncertain number of soldiers were killed or injured as Cambodia and Thailand exchanged artillery fire across the border. The temple is at the centre of a long-running territorial dispute, and although Thailand no longer makes any official claim to the historical site itself, some Thais believe that the land around the temple belongs to Thailand, a claim vehemently denied by Cambodia.

The crossborder clash came soon after the February 1st sentencing of two Thai activists for espionage, entering Cambodia illegally and unlawfully entering a military base. Veera Somkwamkid, a leader of the Thailand Patriot Network (an offshoot of the royalist-nationalist yellow-shirted protest movement, the People's Alliance for Democracy), and one of his aides, Ratree Pipatanapaiboon, received eight- and six-year prison terms respectively, after having been arrested in Cambodia's northern Banteay Meanchey province in January. The prime minister of Thailand, Ahbisit Vejjajiva, had also recently objected to Cambodian flags at Wat Keo Sikha Kiri Svara, a relatively modern Buddhist pagoda situated close to the 11th-century Hindu sanctuary of Preah Vihear.

According to the Cambodian information minister, Khieu Kanharith, the first clashes began on February 4th when Cambodian troops fired warning shots to discourage Thai troops from entering Cambodia to destroy Wat Keo Sikha Kiri Svara. The Thai soldiers responded with shelling after a two-hour firefight, the minister said. Troops from the two sides again exchanged fire on the morning of February 5th using heavy weapons including rockets, machine guns, mortars and artillery for more than an hour. Despite a ceasefire having been declared the day before, further clashes took place on the evening of February 6th, with initial gun, mortar and rocket fire giving way to artillery barrages. Cambodia claimed that Thai artillery shells had landed deep within Cambodian territory. Thousands of civilians on both sides of the border were evacuated, but refugees began trickling back slowly after a ceasefire was declared on February 20th.

As was the case during previous periods of tension with Thailand, Cambodia's prime minister, Hun Sen, has positioned himself to benefit from an upsurge in Cambodian nationalism, appointing his son, Hun Manet, as commander of the forces at Preah Vihear. Hun Sen denounced Thailand's "armed aggression" and claimed that Preah Vihear temple, a UN Education, Scientific and Cultural Organisation (UNESCO) World Heritage Site, had been damaged by Thai artillery. A Cambodian army source claimed that an entire wing of the temple had collapsed during the bombardment, although other reports suggested that damage was mostly confined to shrapnel pockmarks.