Burundian soldiers killed 31 suspected rebels and detained another 170 in a forested area in the country’s north, said military spokesman Gaspard Baratuza.

One civilian was killed and six soldiers were wounded in the clashes, Baratuza said on Monday by phone. The army was acting on information that a band of armed rebels was roaming the remote region, which borders Rwanda, said Baratuza. The group is being investigated, he said, without elaborating.

Burundi, a landlocked coffee-producing nation, has been facing unrest since an announcement in April that President Pierre Nkurunziza will be running for a third term, sparking an outcry by opponents who say he’ll violate a two-term limit. The decision triggered a failed coup attempt and protests that have left 77 dead, forced another 100,000 to take refuge in neighboring countries and prompted several delays to the presidential vote. It’s currently scheduled for July 21.

The violence has raised fears of a return to conflict if rebel groups abandon a 2005 peace accord that ended a 12-year civil war, during which 300,000 people were killed. It also has the potential to destabilize the Great Lakes region, which includes Rwanda where a genocide took place in 1994.

The United Nations has warned that the East African nation risks sliding back into violence and said voting last month for lawmakers was not“free, credible and inclusive.”