Brigade 5 of the Karen National Liberation Army (KNLA) said 42 regime soldiers and eight anti-regime fighters were killed during 99 clashes in Mutraw (Papun) District, Karen State, during March.
It said army officers were among those killed and 55 junta troops and 14 anti-regime fighters were injured.
The junta responded with drone attacks, airstrikes and shelling, using around 1,500 bombs, including attacks on civilians, the armed group said.
The Irrawaddy could not independently verify the reports.
On Sunday, junta aircraft bombarded a Buddhist monastery sheltering civilians displaced by fighting in Papun town, killing eight civilians, including a monk and a pregnant woman, and injuring 15 others, residents told The Irrawaddy.
The KNLA and its allies have been attacking junta bases in Papun for about two weeks, seizing the town in the northern tip of Karen State near the borders with Bago Region, Karenni (Kayah) State and Thailand.
An estimated 1,624 civilians from Papun have been displaced, according to the political wing of the KNLA, the Karen National Union (KNU) in Mutraw District.
Mutraw District has reported the destruction of over 40 buildings and the deaths of around 20 livestock in junta airstrikes.
The KNU on Tuesday reported clashes in Doopalaya District of southern Karen State between March 15 and 25 amid junta attempts to retake Light Infantry Battalion 355 headquarters in Thingyan Nyi Nyaung town, Myawaddy Township.
Around 20 regime troops were killed and many others injured during the fighting. The anti-regime groups seized many weapons and ammunition from junta troops and a resistance member was killed and four others injured, the KNU said.
Junta shelling and airstrikes caused civilian casualties and destroyed many houses, the group said.
The KNU and its allies are attacking regime targets in Mon and Karen states and Bago and Tanintharyi regions alongside several resistance groups, including People’s Defense Forces loyal to the civilian National Unity Government.
