The fighting broke out near two temples in the Phanom Dong Rak of southeastern Thailand's Surin province, Thai army spokesman Col. Sunsern Kaewkumnerd said.

Authorities were evacuating people living in a nearby village, the MCOT news agency reported.

Sunsern said the cause of clashes "is not yet known."

At least 10 people were killed when renewed fighting flared up in another disputed border area between the two nations in February, prompting the UN Security Council to issue a statement calling on both sides to implement a permanent cease-fire and "resolve the situation peacefully and through effective dialogue."

Those clashes, which lasted four days, stemmed from a longstanding conflict related to the 11th-century Preah Vihear temple. Both Cambodia and Thailand lay claim to the temple, which sits atop a cliff on Cambodian soil but has its most accessible entrance on the Thai side.

At the time, each nation accused the other of firing first, according to a statement from the Association of Southeast Asian Nations.