Thailand yesterday lodged a high-level diplomatic protest over serious Burmese military incursions into Thai territory that caused a royal tour to be cancelled and foreign tourists to flee.
Witnesses said two young Thai women and a young Thai man were killed when Burmese artillery shells hit a house in the town of Mae Sai.
"Two of them were sitting on chairs and one on the floor when a shell exploded only a meter or two away from them," said an American gem dealer Joe Efparza. "They didn't have a chance."
Visiting Queen of Denmark Margrethe II cancelled a visit to the region yesterday because of the border fighting. The queen and her husband, Prince Henrik, are on a six-day state visit to Thailand.
Foreign tourists, including Australian backpackers, fled along with thousands of Thais.
The bridge which links Mae Sai with the Burmese town of Tachilek was reopened to allow civilians to return to their homes.
But Mr Efparza said the situation remains tense.
"More troops are coming in and taking up positions and they have brought in a couple of helicopter gunships," he said.
The Burmese also hit a Buddhist temple.
Tensions increased late last week when Burmese troops seized a strategic hill on Thai soil, near the village of Ban Pang Noon, as part of a counterattack against the Shan State Army.
Thai troops recaptured the hill yesterday, claiming that nearly 100 Burmese soldiers were killed. Shan had, in recent weeks, attacked Burmese positions as part of a campaign to secure an autonomous Shan State.
The insurgents also had destroyed heroin and methamphetamine factories operated by the United Wa State Army, an ethnic militia aligned with Burma's junta.
The growing power of Wa had raised fears that more drugs would be sold in Thailand and more cheap heroin smuggled to Australia.
The Thai Government called Burmese ambassador Hla Maung into the Thai Foreign Ministry yesterday to register its concern.
"Burmese troops have violated the country's sovereignty and territorial integrity," senior Thai Foreign Ministry official Surapong Jayanama said.
"The Thai army responded directly to the violation, which Thailand regards as provocative."
Witnesses confirmed that the Thai military had fired canon and artillery barrages at Burmese forces.
-Sydney morning herald and associated press