Thai and Cambodian troops clashed for a fourth straight day Monday over a disputed border area surrounding a 900-year-old Hindu temple as Cambodia urged the U.N. Security Council to intervene.

Shelling and machine gunfire resounded in the morning in the 4.6-sq-km (two-sq-mile) contested area around the 11th-century Preah Vihear temple on a escarpment covered in jungle and claimed by both Southeast Asian neighbours, witnesses said.

Fighting in the area killed at least five people Friday and Saturday, the deadliest clashes since Cambodia's bid in 2008 to list the ruins as a World Heritage Site sparked sporadic exchanges of fire in the rugged area.

Cambodian Prime Minister Hun Sen called on the Security Council to convene an urgent meeting, accusing Thailand of repeated acts of aggression that have killed Cambodians and caused a wing of the temple to collapse.

U.N. Secretary-General Ban Ki-moon said in a statement he was deeply concerned and urged both sides to cease fire and find a lasting solution to the dispute.

The number of fatalities is unclear.

The Cambodian government has said three of its nationals, including two soldiers, have been killed. Thai media say as many as 64 Cambodians died, quoting army sources. That could not be verified by witnesses contacted by Reuters in Cambodia.

The Thai army says a soldier and a villager were killed on Friday and Saturday and that at least 20 soldiers were wounded. Cambodian media say the toll is higher.

At least 2,500 people have fled villages on the Thai side of the border and hundreds of Cambodians have been evacuated, according to witnesses and local authorities in both countries.

Although sporadic clashes are not unusual, it is rare for the two sides to fight over consecutive days.

The United States has called on both countries to show restraint. The Association of South East Asian Nations, a regional forum of which both Thailand and Cambodia are members, said Saturday the deteriorating situation was undermining confidence in the region and would affect its economic recovery.

PROTESTERS SEEK THAI PM RESIGNATION

The two neighbours have been gripped by on-again off-again tension. Each side accuses the other of infringing on its territory.

Relations with Cambodia have become a bone of contention in long-running hostility between Thai political factions.

Pro-establishment Thai yellow shirt activists accuse their main rival, ousted premier Thaksin Shinawatra, of colluding with Cambodia to Thailand's detriment.

The yellow shirts, which helped to bring Prime Minister Abhisit Vejjajiva to power, have turned against him, demanding he take a tougher line against Cambodia.

Up to 4,000 gathered outside his offices Saturday and 1,500 Sunday calling for his resignation.

The temple, known as Preah Vihear in Cambodia and Khao Phra Viharn in Thailand, sits on land that forms a natural border and has been a source of tension for generations.

The International Court of Justice awarded it to Cambodia in 1962 but the ruling did not determine the ownership of the scrub next to the ruins, leaving considerable scope for disagreement.