Thailand and Cambodia Clash Again in Border Dispute

BANGKOK — Thai and Cambodian troops clashed for a third day on Sunday in the first major territorial encounter since an informal cease-fire that followed four days of fighting in February. At least 10 people were killed and thousands of residents were evacuated from border areas, according to reports from both sides.

The United Nations called on the countries to settle the conflict peacefully, with an effective and verifiable cease-fire. The exact cause of the latest clash, which began early Friday, was unclear, with the two sides accusing each other of making the first move in what was mostly a long-range artillery duel.

The fighting was reported at border areas 100 miles west of Preah Vihear, an 11th-century temple that has been the focus of armed tensions since it was listed in 2008 by the United Nations as a World Heritage site under Cambodian administration.

Both nations claim ownership of a strategic area of 1.8 square miles near Preah Vihear. Two other ancient Hindu temples in the border area are the focus of the latest eruption of fighting.

In his weekly television address, the prime minister of Thailand, Abhisit Vejjajiva, accused Cambodia of starting the fighting. “When there is firing into Thailand, we must fire back,” he said.

Mr. Abhisit added: “We must not fall into Cambodia’s trap in trying to spread a picture of conflict, or say the conflict is unsolvable through bilateral talks.”

A sticking point in efforts at negotiations is Thailand’s resistance to Cambodia’s demand for mediation by international bodies. In the past, outside judgments have favored Cambodia. In 1962, the World Court ruled that Preah Vihear, which stands on a border bluff overlooking the Cambodian countryside, belonged to Cambodia.

The disputes involve border demarcations between the two countries made by former French colonial administrators and include references to competing maps and interpretations of maps.

The conflicting claims are a rallying cry for nationalists on both sides. In Thailand, they have become a focus of the antigovernment “yellow shirt” protests in recent months.

In February, the United Nations forwarded a Cambodian request for mediation to the Association of Southeast Asian Nations in which both sides agreed to allow unarmed military observers to be posted along the border.

But the Thai military resisted that plan, and the country’s foreign minister, Kasit Piromya, said that his government was trying to secure the cooperation of the armed forces to find a peaceful settlement.

Cambodia accused Thailand over the weekend of firing artillery shells “loaded with poisonous gas” and of flying jet fighter sorties over Cambodian territory. Thailand rejected the accusations as groundless.