Myanmar, also known as Burma, says ethnic rebels attacked an army outpost near the border with China last week, killing seven soldiers and wounding 20 others.
State-run media reports Monday say Kokang fighters surrounded the post for two days in northern Shan State.
The Ta'ang National Liberation Army (TNLA), which is allied with the Kokang guerrillas, says fighting in the area was still ongoing Monday. Tar Phone Kyaw, secretary of TNLA, disputes the government account and blames the Army for the violence.
“The area where fighting took place this week are controlled by our groups - TNLA and Kokang, then the fighting took place because the government troops entered the area. We didn't make any strikes against military outposts held by government forces," said Kyaw.
Other than the state-run media reports, government and military officials have not commented on the fighting. And casualty figures were not known.
The Kokang was formerly a pro-communist fighting force that battled the government until signing a ceasefire in 1989. Fighting resumed in 2009.
Meanwhile, the government says it has held talks in Chiang Mai, Thailand with the Nationwide Ceasefire Coordination Team (NCCT), an umbrella group that represents several ethnic rebel movements.
Hla Maung Shwe, a member of the government's Myanmar Peace Center, tells VOA he is optimistic formal negotiations will resume this month.
“We discussed resuming talks at Yangon's Peace Center. They said they can return to talks before December 25, Christmas. I think we may have peace talks between the 20th and 25th of December at Yangon," said Shwe.
The two sides have met several times since the NCCT was founded in July, but there has been no progress reported.
Most of the ethnic groups in Myanmar have been fighting for decades and have separate, temporary cease-fire agreements with the government.
This report was produced in collaboration with the VOA Burmese service.