At least 49 people have been killed overnight in northeast Nigeria in two separate incidents of violence, including fighting between Nigeria's military and the radical Islamist sect Boko Haram.

Fighting between military and the Boko Haram killed at least 24  insurgents in Maiduguri, the capital of Borno state on Monday.

Spokesman of the military Joint Task Force (JTF) Lt Col Sagir Musa said Boko Haram sect members attacked JTF locations in Zannari ward and Lagos street along Gwange general area on Monday night leading to the confrontations.

According to him rocket propelled grenades and improvised explosives device were used by the insurgents in the attacks.

"All the attacks were repelled, 24 Boko Haram terrorists were killed," Musa said, refuting an earlier media report that the insurgents killed 10 civilians.

The commercial nerve centre of the town called the Post Office area was also hit by several explosions.

In a separate incident in Benue state, herdsmen believed to belong to Fulani community killed 25 persons in Yogbo.

Eyewitnesses said those killed in Benue were mostly children and women. Attacks by Boko Haram and Fulani herdsmen have led to several deaths in several states of northern Nigeria.

Boko Haram has been launching guerrilla attacks against Nigeria's weak central government for months as part of its efforts to free its imprisoned members and enact strict Islamic law across the multi-ethnic nation largely halved between Christians and Muslims. In recent days, it has begun a renewed offensive in Maiduguri.