YANGON: Rebel troops clashed with government soldiers in eastern Myanmar Monday after rare elections, leaving three civilians dead as more than 10,000 fled across the Thai border, officials said.
Fierce fighting between ethnic minority soldiers and government forces in Karen State drove thousands across the border -- mostly women and children -- said Samart Loyfah, the governor of Thailand's Tak province.
"Army, police and civil authorities have prepared an area to accommodate them five kilometres (three miles) from the border," he said.
In Myawaddy, a town in an insurgency-plagued region in southeastern Myanmar, people hid in homes, seeking out buildings with bomb shelters.
One resident said there were so many explosions he could not count them and expressed fears that the conflict could intensify overnight.
"People are running here and there -- it's desperate. We could be killed at anytime, this is very scary," he said.
At least three people died and around 20 more were injured, said an unnamed official in the military-ruled country, who did not give troop casualty numbers for either side.
Fighting between rebels and the army further south in the Three Pagodas Pass border area caused another 1,000 people to cross in to Thailand's Kanchanaburi province, said a local Thai district chief, Jamrus Srangnoi.
Zipporah Sein, the Thailand-based general secretary of the Karen National Union (KNU), said there had been clashes between government forces and Democratic Karen Buddhist Army (DKBA) troops in the two areas.
"I don't think the DKBA will surrender," she added, warning that armed KNU forces could join the fight.
On the Thai side of the border, a rocket propelled grenade landed in Mae Sot, near Myawaddy, injuring several people. Four more were fired into Kanchanaburi, but no one was injured.
The Myawaddy clash followed an armed demonstration by the rebels in the town over Sunday's election as well as attempts to force ethnic minority troops to join a "border guard force" -- which would put them under state control.
It was unclear exactly what sparked the violence.
A simmering civil war has wracked parts of the country since independence in 1948 and observers say the state's determination to crush ethnic rebels appeared to increase as elections loomed.
Thai Prime Minister Abhisit Vejjajiva warned that ethnic unrest could last months after Myanmar's controversial poll and said his country would not "interfere in Myanmar's domestic affairs".
Last week the Democratic Voice of Burma (DVB), an exiled media organisation, reported that six armed groups in Myanmar's troubled ethnic minority areas had agreed to help each other fight back if attacked by government forces.
Many groups have previously signed ceasefire agreements with the junta, but tensions have increased, with fierce resistance to the government's border guard force plan.
In areas where civil war continues, rights groups have accused the junta of waging a brutal counter-insurgency campaign involving the rape, torture and murder of villagers, whose homes are routinely destroyed.
The military has ruled the country since 1962 and the armed forces have doubled in size over the past two decades, to up to 400,000 personnel.
An offensive against ethnic Chinese Kokang rebels in the northeast in August 2009 caused tens of thousands of people to spill over the border, earning the junta a rare rebuke from China.
The Myanmar authorities, citing security concerns, scrapped voting in swathes of ethnic-minority areas in Sunday's election, widely decried as a sham to maintain military rule.