Lao troops occupying territory south of the Sekong River withdrew on Saturday after Prime Minister Hun Sen gave them a six-day deadline to leave and dispatched two military brigades and members of his personal Bodyguard Unit to the border.

The swift mobilisation, announced on Friday morning, followed a months-long stalemate over a contested piece of border land in Stung Treng province, where Lao forces have blocked Cambodian military engineers from building a road.

On Saturday, Hun Sen appeared in Laos with his Lao counterpart, Thongloun Sisoulith, who apologised for not responding to a direct request by Cambodia’s premier to remove Lao forces from the area in Siem Pang district.

“Laos will withdraw its troops by [Sunday] morning,” Sisoulith said. “The border committees will negotiate about the border [issue] to demarcate it soon”

Tensions about disputed territory between Cambodia and Laos have rumbled for more than a year, and boiled over in February when a few hundred Lao troops crossed the Sekong to halt the construction of a road skirting Cambodia’s border. According to a summary of the meeting between the two premiers on Saturday, 14 percent of the border between the two countries is un-demarcated.

That initial standoff in February was briefly resolved and construction continued until April, when Laos set up a semi-permanent camp to block the engineers, whose road project is set to skirt Cambodia’s northern boundary and join with another section in Ratanakkiri province.

“There were about 400 Laotian troops in that area, four units comprised of 100 personnel,” said government spokesman Phay Siphan.

“On the Cambodian side they stationed about 70 to 80 from the morning, and left about 40 at night.”

Cambodian soldiers in Stung Treng’s Siem Pang district prepare to take a boat yesterday to the Lao border, where troops had been engaged in a standoff with their Lao counterparts. Heng Chivoan

Post reporters were yesterday blocked by a border police official from visiting the remote contested area, known as O’alay, in Santepheap commune.

At an outpost about 30 kilometres away called O’ Kuk, two of the military engineers who worked on the road said Lao soldiers had set up tents within a stone’s throw of the Cambodian troops and claimed they were on their land.

“The Laotians said they had been stationed there since French colonial times but Cambodia did not access that area,” said one of the engineers, who requested anonymity for fear of repercussion.

Nearby, a 53-year-old border policeman, who returned from the contested zone last week, said the camps were a few dozen metres apart. On the Cambodian side, military troops formed the central force with police units on their flanks, he said. “Mostly we just patrolled in groups of 10,” said the policeman, who also requested anonymity.

“It was tense. We have had no communication with the Laotians since April . . . but I’m not scared. If they shoot at us, we would shoot at them.”

The policeman said extra soldiers arrived on Saturday morning and crossed into the contested area, though he was not sure of the unit.

According to the premier, the Kampong Cham-based Brigade 21 was mobilised, as was a brigade from Intervention Division 2, understood to be Brigade 6.

Photos also circulated of a truck-mounted rocket battery from the Prime Minister’s Bodyguard Unit being prepared for transport on Friday and driving past Phnom Penh’s Independence Monument early on Saturday.

Reached yesterday evening, Defence Ministry spokesman Chhum Socheat said the “Laos military invaders” had withdrawn by 4pm on Saturday, and the mobilised Cambodian forces had also returned to their bases.

“The situation at the area has returned to normal. There is no problem anymore,” he said, adding he could not confirm when construction on the road would resume.

“The [prime minister] and his counterpart met in Laos [and] the border committee from the two countries will talk about the border issue.”

Sok Touch, the head of Cambodia’s Royal Academy, who previously investigated alleged border encroachment by Vietnam in the east, yesterday visited the site, as did the premier’s eldest son, Hun Manet, a lieutenant general who holds several leadership positions in the Royal Cambodian Armed Forces, according to government-aligned media outlet Fresh News.

Touch was unreachable yesterday, though on Saturday he said he would document what had happened on the remote frontier.

Paul Chambers, of the College of ASEAN Community Studies at Thailand's Naresuan University, said Laos may have been motivated by a desire to protect the area’s lucrative trade in natural resources, such as timber, which he noted the Laotian military was “heavily involved” in.

Hun Sen’s “bombastic” response, meanwhile, appeared aimed at a domestic audience.

“In this case, once again, Hun Sen uses the nationalism card against regional weakling Laos to try to unite Cambodians behind him,” Chambers wrote via email.

“I think this situation has become a worsening border dispute but Hun Sen is now turning it into a source for domestic nationalism which he can use to benefit himself and his political party.”