A resistance group fighting Myanmar's military rule said on Sunday its fighters had repelled an attempt by junta troops to advance on the key town of Myawaddy along the Thai border that was seized by the rebels last week.

Reinforcements of junta forces have been trying to advance on Myawaddy for days, but were pushed back in a battle about 40 kilometers 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 difficulty," he said, mentioning the KNU's forces had been "blocking and intercepting" the junta troops.