BANGKOK Seven Myanmar soldiers were killed in an early Sunday attack on their camp by separatist Shan guerrillas in northeastern Myanmar's Shan State, Thai military sources said.

Shan State Army guerrillas captured the Myanmar Army outpost at Tuan, opposite the Thai town of Fang, some 700km (420 miles) north of Bangkok, and seized about 170,000 methamphetamine tablets, the Thai sources said.

Nearly 500 Thai villagers were evacuated from their homes in Fang after the clash due to fears of an upsurge in fighting between the Shan rebels and Myanmar forces, Thai authorities said.

In another incident, two members of a Myanmar ethnic minority militia allied with the military government were killed on Sunday in an attack by unidentified rivals in the east Myanmar border town of Myawady, Thai military sources said.

"At around 4:00 a.m. (2100 GMT) an unidentified rebel group, armed with rifles and mortars, opened fire on the DKBA troops for about half an hour," said a Thai military source based on the Myanmar-Thai border, cited by Reuters.

Two fighters from the Democratic Karen Buddhist Army (DKBA) were killed and two wounded in the attack. Two villagers were also wounded, the Thai sources said.

The DKBA and Myanmar government forces fight the autonomy-seeking Karen National Union (KNU) guerrilla army in that part of eastern Myanmar but the KNU had not claimed responsibility for the attack, the Thai sources said.

The area of the attack is believed to be one of Myanmar's main areas for producing illegal methamphetamines, which have been flooding into Thailand in recent years.

Thai military sources say the DKBA, formed by a KNU splinter faction in 1994 after a split in the Christian-led, anti-Yangon group, is involved in the drugs trade.