LAGOS, Dec. 23 -- The Nigerian defense authority on Monday said more than 70 people have been killed in clashes between the army and members of the Boko Haram militant group in the northeast, following last Friday pre-dawn attacks on a military barracks in Bama town.

"Over 50 of them (Boko Haram) died in the course of exchange of fire with ground troops in the ongoing operations to apprehend fleeing terrorists," Major General Chris Olukolade, the defense director of information, said in a statement obtained by Xinhua.

He said the military also lost 15 soldiers mostly from the attack while some died during the pursuit, adding that a total of five civilians also died during the attack.

According to Olukolade, the military operations led to the destruction of over 20 vehicles conveying escaping militants.

He added that the vehicles were the ones used during the attack on the barracks and were sighted through air surveillance as the militants were making efforts to cross the borders back to their haven in Cameroon.

Last Friday, the military said Bama barracks was attacked by militants who came from cells located across Nigerian Border with Cameroon through Banki town, adding that high caliber weapons such as anti-aircraft and rocket propelled guns were freely used in the attack that lasted several hours.

Bama town, about 65 km from Maiduguri, the Borno State capital, had suffered numerous attacks from Boko Haram insurgents, forcing some residents to flee.

Many residents were killed in May when suspected militants raided Bama Town, killing mostly children and women.

Violence has intensified in northeastern Nigeria since President Goodluck Jonathan ordered his security forces in May to crush Boko Haram's four-year-old rebellion.

The Nigerian forces have been raiding militant camps and launching air and ground attacks on suspected hideouts of the militants over the past two months.

Borno State, located in Nigeria's northeast region, is a flashpoint of attacks perpetrated by Boko Haram since 2009, when the sect launched its insurgency targeting churches, security facilities, schools and villages.