The Karen National Union, which is fighting the army near Myanmar’s eastern border, said on Tuesday that it had occupied and burned an army outpost.
The group’s foreign affairs chief, Padoh Saw Taw Nee, told the press that the group was still determining deaths and casualties, and that there were clashes elsewhere as well, but he did not elaborate.
In recent weeks, army airstrikes have forced more than 24,000 people to flee their homes in the border region, according to the Free Burma Rangers aid group.
The Karen National Union, like other ethnic minority representatives, have sided with the protesters, who are demanding the return to power of the elected government.
The latest clashes took place days after Myanmar’s Junta Chief Min Aung Hlaing attended a regional summit in Jakarta, where he agreed to end violence and engage in dialogue.
The meeting of the Association of Southeast Asian Nations (ASEAN) marked the first concerted international effort to find a solution to the crisis.
More than 750 people have been killed by security forces, including dozens of children, since the February 1 coup, and some 3,400 have been detained, according to the National Association for Assistance to Political Prisoners.