Nervous Cambodian residents dug bunkers or evacuated homes Monday as the UN awarded land surrounding an ancient temple to their country, an issue which has sparked deadly clashes with neighbouring Thailand.
At least 28 people have been killed in outbreaks of violence since 2011 over the ownership of a patch of border land next to the 900-year-old Preah Vihear temple.
The issue inflames nationalist sentiment in both countries -- not least because both governments, experts say, have used it to drum up support or as a distraction from domestic politics.
A judge at the International Court of Justice at The Hague interpreted a 1962 ruling saying that "Cambodia had sovereignty over the whole territory of the promontory of Preah Vihear".
There are fears the decision will revive nationalist tensions and could spark renewed clashes.
Thailand's prime minister was due to give a television address on the issue on Monday evening.
Tens of thousands of people were displaced in the fighting, leading Cambodia to ask the ICJ for an interpretation of the original 1962 ruling on ownership of the contested parcel of land.
Thailand does not dispute Cambodia's ownership of the temple, a UNESCO World Heritage site, but both sides claim an adjacent 4.6-square-kilometre (1.8-square-mile) piece of land.
Leaders of the two countries appealed for calm before the ruling by 17 international judges.
The mood on both sides of Preah Vihear temple was tense Monday ahead of the ruling, with tourists still allowed to visit the ancient structure via Cambodian territory. But journalists were denied access.
Earlier Monday, villagers said they were taking no chances.
"We have already prepared our bunkers in case Thai troops open fire," So Phany, a vendor near Preah Vihear temple, told AFP.
Other villagers along the border with Thailand left their homes altogether, fearing the worst, said an AFP photographer at the scene.
Dozens of locals near the temple complex crowded around grainy television screens in coffee shops as the ICJ began the live broadcast of its deliberations.
The Cambodian army denied local media reports that it had sent military reinforcements to the area.
"The situation along the border is normal," regional military commander, General Srey Doek, told AFP.
On the Thai side, some 40 primary schools were closed in one district on the border, according to a provincial education official, Somsak Chobthamdee.
A local village headman said a number of villagers had left to stay with families.
On her Facebook page Thai Prime Minister Yingluck Shinawatra vowed Sunday to "consult" with Cambodia after the decision to avoid any conflict.
The ruling was fraught with danger for her government, which is already grappling with mass street demonstrations against a controversial political amnesty bill.
The country's opposition is likely to direct public anger over the ruling towards Yingluck, whose divisive brother Thaksin is close to Cambodia's strongman premier Hun Sen.
Cambodia has allowed Thaksin -- who is in exile from Thailand to avoid a jail term -- to hold a number of rallies for his "Red Shirt" supporters on its soil.
Last year the ICJ ruled that both countries should withdraw forces from around the ancient Khmer temple, which is perched on a clifftop in Cambodia but is more easily accessed from the Thai side.
Cambodia and Thailand finally pulled hundreds of soldiers from the disputed zone in July 2012, replacing them with police and security guards.
In a television appeal last week Hun Sen urged his armed forces to "to remain calm and show restraint", adding he had agreed with his Thai counterpart to abide by the ICJ's decision.
The roots of the dispute lie in maps drawn up in 1907 during French colonial rule.