Reinforcements of junta forces have been trying to advance on Myawaddy for days, but were pushed back in a battle about 40 kilometres away, a spokesperson for the Karen National Union (KNU), Saw Taw Nee, said in an interview.
"It is not easy to come here. They face a lot of difficulties," he told Reuters, saying the KNU's forces had been "blocking and intercepting" the junta troops.
The KNU information could not be independently confirmed. A spokesperson for the military junta that seized power from an elected government a 2021 did not answer calls from Reuters.
The border town of Myawaddy, adjacent to Thailand, was wrested from military control by a coalition of anti-junta forces led by the KNU on Thursday.
Fighting took place on Friday between the villages of Kawkareik and Kaw Nwet along the main Asian Highway 1 leading west from the Thai border, Saw Taw Nee said.
The KNU spokesperson said information received from the front line put the junta's toll of deaths and injuries from the fighting at around 100. "We know that they suffered a loss of one-armed carrier and a military truck," he said.
Myanmar has been in turmoil since 2021, when the powerful military deposed an elected civilian government, triggering widespread protests it sought to crush with force.
Simmering anger against the junta turned into a nationwide armed resistance movement that is now increasingly operating in coordination with established ethnic rebel groups to challenge the military across large parts of Myanmar.
Saw Taw Nee said the resistance "will take time." "We need to have a kind of coordination with other groups… to defeat the military," he said.
The KNU spokesperson said there were also challenges working in a broad anti-junta coalition.
"We are still in the process of how to negotiate, how to come together and how to move forward among our Karen groups," he said, referring to members of the ethnic group residing primarily in Kayin State.
Saw Taw Nee said the immediate concern for the KNU is the more than one million displaced people within its territories, and called on the international community, including neighbouring Thailand, to provide support.
"We really need to work together in the future more and more on this issue," he said.
He urged Myanmar's junta to see their recent military setbacks as a sign that they should hand back power to the people.
"Please don’t waste time any more," he said. "This is the time, and a good opportunity, to listen to people first."
Reuters