Nearly 50 Ta’ang National Liberation Army (TNLA) soldiers were killed in more than 30 days of fighting for the junta’s major Sakham Thit Kone base outside Namkham town on the Chinese border in northern Shan State.
The Sakham Thit Kone camp frequently shelled the captured town until it fell on Monday night.
The TNLA seized Namkham town on November 7 after attacking junta bases and the township police station as part of Operation 1027 which was launched with the Myanmar National Democratic Alliance Army (MNDAA) and the Arakan Army (AA), the other two members of the Brotherhood Alliance.
More than 150 junta soldiers, including many wounded, led by Major Myint Kyaw surrendered at Sakham Thit Kone. Pictures show a large haul of seized weapons and ammunition.
The TNLA said it had seized 19 junta positions, including Sakham Thit Kone, in Namkham in less than two months.
On Tuesday a TNLA announcement said 49 of its members were killed and 145 injured at Sakham Thit Kone.
It added that Namkham was one of the many places where lives, blood and sweat had been lost during Operation 1027.
The bodies of junta soldiers, up to the rank of major, were discovered, it said. Around 900 junta soldiers had been based in Namkham under No.7 Military Operation Command, according to the Brotherhood Alliance.
Numerous junta airstrikes and artillery strikes were used to defend the base and attack Namkham town, the alliance said.
At least 13 civilians, including three children, were killed and 43 injured by junta bombardments during the operation, the TNLA said.
A total of 94 buildings, including religious buildings, hospitals and houses, were destroyed by junta artillery and airstrikes, it said.
The TNLA troops are also attacking junta bases at Kutkai and Manton in northern Shan State.