Thai and Cambodian soldiers were in a stand-off on Wednesday after a brief exchange of gunfire in a disputed border area of the northeastern province of Ubon Ratchathani early that morning.

One Cambodian soldier was killed in the exchange, the defence ministry in Phnom Penh said.

“The Thai army first opened fire on a trench that had been a Cambodian army base for a long time, resulting in the loss of one of our soldiers,” the ministry said in a statement.

Thailand said its soldiers were trying to negotiate with Cambodian troops to back away from taking up a position in a disputed area but came under fire.

“Cambodian forces misunderstood the situation and started using weapons, so Thai forces retaliated,” army spokesman Maj Gen Winthai Suvaree said, adding that there were no Thai casualties. The exchange lasted about 10 minutes.

Deputy commanders of the local Thai and Cambodian forces subsequently talked by phone and agreed on a ceasefire, but soldiers from both sides remained at the scene, Maj Gen Winthai said.

The incident occurred near Chong Bok in Nam Yuen district of Ubon Ratchathani about 5.30am.

According to Matichon Online, the Cambodian soldiers were digging a trench in the disputed area. It published a photo of what it said was the trench. There were no soldiers in the photo.

Lt Gen Boonsin Padklang, commander of the 2nd Army which oversees the Northeast, said Thai soldiers on routine patrol saw Cambodian soldiers “changing the geographic aspect of the disputed area” and asked them to stop what they were doing.

The Cambodians responded with gunfire, sparking the brief clash, he said. Local authorities on both sides were discussing the situation, he said.

The 2nd Army chief also said soldiers on both sides should return to their normal positions to prevent a recurrence of hostilities, and await the outcome of high-level negotiations on the demarcation of the area.

Defence Minister Phumtham Wechayachai said Cambodian soldiers had dug trenches in the disputed area for the second time. When Thai soldiers saw them securing the newly dug area, the Cambodian side opened fire, he said.

After the clash, a military officer close to Cambodian Defence Minister Tea Seiha phoned Thai Deputy Defence Minister Gen Natthapon Nakpanich and suggested the two sides reduce confrontation, Mr Phumtham said.

He confirmed that Thai and Cambodian soldiers remained at the site of the clash.

“I received a report from the area that the situation made the shooting response necessary for self-defence and the protection of Thai sovereignty,” Mr Phumtham said.

“I told them to take precautions. Although the gunfire stopped, forces from both sides remain at the confrontation site.”

Deadly clashes between Cambodia and Thailand last erupted in 2011 over Preah Vihear, an ancient temple at the heart of a decades-long dispute on their undemarcated border.

Another more recent flashpoint was Prasat Ta Muen Thom, an ancient Khmer temple on the border in Surin province, where a brief confrontation took place in February. On May 2, military officials from both countries held talks and agreed to withdraw their troops from the site.

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