At least 45 Nigerian security personnel are dead after gunmen believed to be Boko Haram militants attacked the town of Buni Yadi.
Hundreds of gunmen on trucks and motorcycles stormed the town in northeastern Yobe state late Monday.
A source with Nigeria's Joint Task Force tells VOA's Hausa Service that 24 soldiers and 21 police officers were confirmed dead following the attack.
The source, who spoke on condition of anonymity, said the gunmen took away an armored tank and many vehicles.
There has been no word on civilian casualties.
Major attacks blamed on Nigeria's Boko Haram
July - Attacks prompt government crackdown in Bauchi and Maiduguri; 800 people killed
December - Bombings in central Nigeria and church attacks in the northeast kill 86
June - Attack on a bar in Maiduguri kills 25
August - Suicide bomber kills 23 at U.N. building in Abuja
November - Bombings in Damaturu and Potiskum kill 65
December - Christmas Day bombings across Nigeria kill 39
January -- Gun and bomb attacks in Kano up to 200
February - Maiduguri market attack kills 30
June - Suicide car bombings at three churches kill 21
July - Attacks in Plateau state kill dozens, including two politicians at a funeral for the victims
February - French family kidnapped in Cameroon, held hostage for two months
April - Fighting with troops in Baga kills up to 200; residents say troops set deadly fires
May - Attacks in Bama kill more than 50
July - Gunmen kill 30 at a school in Yobe
August - Gunmen kill 44 at a mosque outside Maiduguri
September - Gunmen kill 40 students at a post-secondary school in Yobe
December - Militants attack military installations in Maiduguri
January - Militants kill 74 people and burn down a village in attacks in Borno and Adamawa
February - Gunmen kill as many as 60 in attack on school in Yobe
April - Militants abduct 276 schoolgirls
A Hausa Service reporter who is in northeastern Nigeria said militants are also attacking motorists on highways leading in and out of Maiduguri, a city in Borno state.
Boko Haram is based in Borno state.
Drivers said snipers wait in trees to fire at passing cars, which are then attacked by gunmen hiding in bushes by the side of the road.
Despite promises of action from President Goodluck Jonathan, Nigerian security forces have been unable to stop the increasingly frequent attacks either claimed by or blamed on Boko Haram.
The twin bombings in the city of Jos last week killed 130 people, and Boko Haram continues to hold more than 200 schoolgirls kidnapped from a school in the village of Chibok last month.
The Islamist radicals have killed thousands of people over the past five years in attacks on schools, churches, mosques, bus stations and other public places.
On Monday, the head of the Nigerian military, Chief of Defense Staff Air Marshal Alex Badeh, said the military knew the location of the abducted Chibok schoolgirls.
VOA spoke by phone with family members of the missing girls about what Badeh called "good news" that the girls had been located.
Those relatives said their hopes have been raised before, but that they will believe the news when the girls are returned home safely.
Nigeria has accepted assistance from the United States and several other countries to help find the girls but has ruled out the use of foreign troops.
VOA's Anne Look in Abuja contributed to this report.