A soldier and 12 militants were killed Saturday in clashes in DR Congo's restive eastern North-Kivu province, the army said.
"Twelve Mai-Mai and an officer from the Armed Forces of the Democratic Republic of the Congo died in fighting that last nearly all of Saturday for control of the Kabasha area," army spokesman Lieutenant Jules Tshikudi told AFP.
The Mai-Mai are vigilante groups that run along ethnic lines. During the brutal Second Congo War between 1998 and 2003, numerous groups were armed by the government to fight against Ugandan or Rwandan forces, and some of them never disarmed.
Saturday's clashes broke out when Mai-Mai fighters attacked the army's position in Kabasha, Tshikudi said, without indicating their ethnicity. The army is now in control of the area, which civilians have fled, he added.
Kabasha lies 24 kilometres (15 miles) south of Beni, a city that has suffered a wave of violence since 2014 with nearly 700 civilians killed, many of them hacked to death.
Those killings have been blamed on the Allied Democratic Forces, a shadowy rebel group dominated by hardline Ugandan Muslims who were initially focused on overthrowing Uganda's President Yoweri Museveni.
Six days ago, more than 900 inmates escaped during an attack on Beni's central prison by armed assailants who have yet to be identified by authorities.
The eastern DR Congo has been rocked by more than 20 years of armed conflict among both domestic and foreign armed groups, fuelled by struggle for control of lucrative mineral resources as well as ethnic and property disputes.