Image caption The Preah Vihear temple was listed as a World Heritage site in 2008

The chief of Cambodia's military forces on the Thailand border has called an emergency meeting after Thai aircraft were seen flying low around disputed land near the Preah Vihear temple.

A helicopter and small spotter plane were seen early on Saturday.

Tension on the border is high ahead of a verdict due on Monday by the UN's highest court on where the border lies around the ancient temple.

Fighting in the area in 2011 left 18 people dead and thousands displaced.

The BBC's Jonathan Head in Bangkok says Cambodian troops have dug trenches and bunkers near the temple and similar fortifications are visible on the Thai side.

However, Cambodian regional commander General Srey Deuk told the BBC on Saturday he expected no problems with the Thai military after Monday's verdict.

He said no troop reinforcements had been brought up to the temple.

A 1962 verdict by the International Court of Justice (ICJ) declared the temple to be Cambodian but did not rule on the area around it.

Cambodia sought a clarification of the ruling in 2011 after fighting broke out.

Both countries have agreed to abide by the ICJ ruling but fears remain that nationalist groups may stir up violence in border villages.

Thai nationalist group the Thai Patriotic Network has already said it will reject any judgement from the ICJ, The Nation newspaper reported.

Cambodian Prime Minister Hun Sen has ordered troops along the border to stay calm.

"I'd like to appeal to all armed forces who are on duty to defend the border to keep calm, exercise utmost restraint and avoid any activities that could lead to tension or clashes," he said in a televised broadcast on Thursday.

He said he and Thai Prime Minister Yingluck Shinawatra had agreed that their two countries "have to comply with this decision and try to maintain peace and stability along the border at any cost".