Security sources and local residents were quoted on Sunday as saying that gunmen from the Islamist militant group Boko Haram had attacked the base in the town of Baga, which houses the headquarters of the Multinational Joint Task Force (MNJTF).
The Reuters news agency cited two separate security sources who said Nigerian troops stationed at the base, located near the shores of Lake Chad, had eventually fled after being attacked by Boko Haram fighters travelling in military vehicles. It said military itself did not immediately respond to a request for comment.
'Several hours' of fighting
The news agency AFP, meanwhile, cited local residents who said the soldiers tried to fight off the Islamist attack in a gun battle that lasted several hours, before deciding to withdraw.
Maina Ma'aji Lawan, the Nigerian senator from Borno, where Baga is located, confirmed the attack on the base.
"They (Boko Haram fighters) came in unbelievably large numbers and overpowered the multinational troops and local vigilantes," he told the AFP.
The number of casualties from the fighting remained unclear on Sunday, but local residents told the AFP that the Islamists had killed several people and set ablaze hundred of homes, as well as looting scores of local businesses. Many locals fled the violence using boats to cross to neighboring Chad via Lake Chad.
Thousands killed in years of violence
Militants with Boko Haram, which means "Western education is forbidden," launched an uprising against the Nigerian authorities in 2009, and are now thought to control large swathes of land in the northeast of the country. Thousands of people have been killed in the conflict.
Boko Haram fighters have kidnapped hundreds of girls and boys in the past year. They are still holding more than 200 schoolgirls who were abducted from the village of Chibok, also in Borno state, last April.
pfd/ipj (Reuters, AFP, dpa)