Gen Leopald Mujyambere

Authorities in Democratic Republic of Congo said they had arrested the deputy commander of a rebel group linked to Rwanda’s genocide, in a blow to a militia at the heart of two decades of conflict in the region.

But in a reminder of ongoing violence in Congo’s conflict-torn east, suspected rebels from another group hacked at least nine people to death near the boundary between North Kivu and Ituri provinces on Friday.

General Leopold Mujyambere, the chief of staff of the Democratic Forces for the Liberation of Rwanda (FDLR), was arrested earlier this week in the eastern city of Goma during a routine police stop, government spokesman Lambert Mende said.

“He was recognised (by) the security services who were there,” Mende told Reuters.

Mujyambere has been transferred to the capital Kinshasa, where the military justice system will decide whether to try him in Congo or extradite him to his native Rwanda, Mende added.

The FDLR includes soldiers and former Hutu militiamen responsible for carrying out Rwanda’s 1994 genocide that killed an estimated 800,000 Tutsis and moderate Hutus.

Its presence in Congo since the genocide has been cited by Rwanda to justify multiple armed interventions in its western neighbour, including during two regional conflicts between 1996 and 2003 that killed millions, mostly from hunger and disease.

Congo’s army launched a military offensive against the FDLR in February last year. The government says it has reduced the group to about 100 fighters but independent analysts say the figure is likely closer to 1,500.

In a blog post, the director of the Congo Research Group at New York University, Jason Stearns, said the capture could point to divisions between the FDLR’s military and political wings.

“While the (Congolese) operations have had little impact on the group’s command structure … this military pressure has exacerbated internal tensions within the group which are difficult to parse but seem to be serious,” he wrote.

At least nine civilians were hacked to death on Friday in three villages along the boundary between Ituri and North Kivu’s Beni territory, local military spokesman Mak Hazukay told Reuters.

A local human rights group said at least 21 people were killed in the raids.

Dozens of similar attacks in Beni since October 2014 have killed more than 500 people. The violence had calmed in recent months until Wednesday, when suspected rebels killed at least 17 civilians in an overnight raid.

Hazukay said he believed the assault was carried out by Ugandan Islamist rebels from the Allied Democratic Forces (ADF) who had fled combat with the army further south.

The government and U.N. mission in the country have blamed almost all of the massacres over the last 18 months on the ADF, which has been operating in eastern Congo since the 1990s.

Analysts say others, including some army soldiers, have also been involved.

(Editing by Joe Bavier and Andrew Heavens)