Fighting near Rutshuru began yesterday and by today the army had captured 68 former M23 rebels and 39 others surrendered, said Maj Ndjike Kaiko.
"We are tracking the fleeing M23 fighters who are seeking to infiltrate Kinyandoni and into the Virunga National Park," he said.
M23 launched its rebellion in eastern Congo in April 2012, becoming the latest group of Tutsi rebels dissatisfied with Congo's government. It was repulsed by UN forces and Congo's army in 2013. Many rebels fled to Rwanda and Uganda before a 2013 peace agreement was signed with the government and the group disbanded.
Uganda's government said that hundreds of members of the rebel group in January fled a military camp there where they had been awaiting amnesty, and cautioned that many had been quietly infiltrating into the general public.
Congo residents said Thursday they are terrified of the group's return. Eastern Congo has been plagued by many armed rebel groups since the Rwandan genocide in 1994.