Fighters thought to belong to the notorious Allied Democratic Forces (ADF) militia killed 10 civilians in two overnight attacks in eastern Democratic Republic of Congo, the army said Sunday.

ADF fighters decapitated eight villagers in the village of Boyo, in the northeast Ituri province, and shot dead two civilians in Kainama, army spokesman Lieutenant Jules Ngongo said.

Soldiers were in pursuit of the attackers, he added.

Local officials confirmed the two attacks, adding that houses were also burned in the violence.

Kainama lies at the extreme north of North Kivu province, where it borders with Ituri. It is just five kilometres (three miles) from Boyo. Both provinces sit on DR Congo's eastern border with Uganda.

The ADF militia are Ugandan Islamic fighters who have made their base in eastern DR Congo since 1995.

While they have not launched raids into Uganda for several years, the militia has been blamed for the killings of more than 800 civilians over the past year in both North Kivu and South Kivu provinces.

While the army has conducted operations against them in the region since October 2019, they have not been able to put a stop to the massacres of civilians.

After a relative calm period in January, its fighters have stepped up attacks on civilians since February in Beni, North Kivu province, and Irumu, in Ituri.

But they are just one of dozens of armed groups that have been operating in the mineral-rich border region of eastern DR Congo for decades now.

One recent report by analysts the Kivu Security Tracker estimated there were at least 122 armed groups active in DR Congo's four eastern border provinces, from north to south: Ituri, North Kivu, South Kivu and Tanganyika.