Cambodia and Laos reached an agreement for Lao soldiers to pull back from their shared border, easing the threat of a military confrontation.
"I appeal to Laos Prime Minister Thongloun Sisoulith to withdraw troops from Cambodian territory without any conditions", Hun Sen said during a ceremony in Phnom Penh.
Hun Sen threatened to expel the soldiers by force if they don't leave the area by August 17.
In a news conference after the meeting, the Lao leader said he had ordered the withdrawal.
"We are friends, but a friend can not step on (our) head", said the mercurial leader, who often leans on ultra-nationalist rhetoric to drum up support, especially ahead of election season. Later on Friday Cambodia's foreign ministry announced that Hun Sen would fly to the Laos capital Vientiane on Saturday to meet with his counterpart to hash out a solution. In 2013 the U.N.'s top court ruled that the area belonged to Cambodia and ordered Thai troops to leave.
Thongloun did not say whether Laos admitted to having sent troops into Cambodia, which says about 30 soldiers from Laos crossed into its province of Stung Treng in April.
Laos wants Cambodia to stop clearing land there for road-building and allow checks by inspection panels from both countries, the official said.
An official at the Lao embassy in Phnom Penh told Reuters on Friday the border area was the subject of a territorial and demarcation dispute.