More than 40 insurgents and four soldiers died in clashes between Nigerian troops and Islamists near the scene where scores of abducted girls are believed to be held in the north of the country.
"The capture of a number of terrorists believed to be the ringleaders of those operating around Alagarmo sparked off a major fight on the outskirts of Bulanbuli, Borno State last night," defence spokesman Major General Chris Olukolade said in a statement on Friday.
"Over 40 terrorists died in the encounter while 4 soldiers lost their lives and 9 were wounded," he said in the statement e-mailed to AFP.
There was no independent confirmation of the military statement although residents around the area said they heard dozens of explosions overnight Friday.
Bulanbuli is between Alagarmo and Sambisa forest where the students, who were abducted early last week, are believed to be held.
The April 14 kidnapping came hours after the deadliest attack yet in Nigeria's capital - a bomb blast at a crowded bus station that killed at least 75 people.
Boko Haram leader Abubakar Shekau claimed responsibility for that attack.
