UN Secretary-General António Guterres has condemned the attacks in Nigeria by terrorists and other extremist groups that have taken a toll on security forces and civilians, especially in Borno.

Guterres, in a statement by his spokesperson, Stephane Dujarric, extended his “heartfelt condolences to the Government of Nigeria and to the families of those who have lost their life”.

A major attack took place at a Nigerian military base in Matete, Borno, carried out by the extremists a week ago, in which scores of soldiers were killed.

The UN chief said several other bases were targeted, according to news reports.

“Those who violate international humanitarian, human rights and refugee law must be held accountable,” Guterres said.

The recent increase in violence stems from a power-struggle between militant factions in the region.

President Muhammadu Buhari had vowed to end the insurgency across the north-east, which is the stronghold of the Boko Haram militant group, founded nearly a decade ago.

The UN chief noted that “national elections are due to be held in February next year”.

“The United Nations stands in solidarity with the Government of Nigeria in its fight against terrorism and violent extremism,” the UN chief said.