Two foreigners suspected to be mercenaries were also captured.
The Nigerian military on Monday said it has cleared and taken over Balmo forest in a military operation that lasted throughout the weekend. The military also said 44 terrorists were killed in a separate operation.
The Director of Defence Information, Chris Olukolade, in a statement said the forest, which stretches from Bauchi through Jigawa States, with links to the fringes of Sambisa forest, was used by terrorists as bases and hideouts for launching attacks.
Sambisa forest is considered the main base of the Boko Haram insurgent group.
Mr. Olukolade said the terrorists and armed gangs operating in the forests were completely rooted out while some were captured during the operation.
Those captured, he said, were two foreigners suspected to be mercenaries.
He said six soldiers were killed in various encounters with terrorists during the weekend while those injured are receiving treatment.
He also said several weapons and equipment including power generating sets, communication equipment, vehicles, motorcycles, foodstuff and kitchen utensils were recovered during the operation.
Also, Mr. Olukolade said that over 44 terrorists have died in Kerenoa and adjoining communities, following an encounter with troops who repelled their attack on the communities.
He said the terrorists who were armed with IEDs and other high calibre weapons, carried out a pre-dawn attack on the communities but met with stiff resistance of the troops.
He said that during the operation, several of them were captured as well as weapons and ammunitions of various calibres.
The spokesperson also said troops on routine patrol around Banki and Miyanti in Borno State during the weekend fought through an ambush laid by terrorists resulting in casualties on both sides. The military casualty was among the soldiers that died over the weekend.
Nigerian troops are battling to defeat the Boko Haram insurgents who have killed thousands of people in Northern Nigeria since 2009.