The Boko Haram faction led by Abubakar Shekau claimed in a video released on social media that its fighters carried out the January 14 attack on Rann, near the border with Cameroon.
Many reports including those from AFP and Reuters have previously attributed the incident to Islamic State West Africa province.
The attack in Rann, some 175 km (110 miles) northeast of the Borno state capital, Maiduguri, began late on Monday afternoon and Nigerian government forces reportedly fled after militants targeted a military base and burned buildings.
Medecins Sans Frontieres (Doctors Without Borders) said on Wednesday that 14 people including three soldiers were killed in the assault on Rann.
Boko Haram split into two factions in mid-2016. One is led by Abu Mus’ab Al-Barnawi and largely focuses on attacking military and government targets, while the other, led by Abubakar Shekau, is notorious for suicide bombings and indiscriminate killings of civilians.
Shekau has pledged allegiance to ISIS leader Abu Bakr Al-Baghdadi, but ISIS central gave its formal backing to the Barnawi faction, which is known as Islamic State West Africa province.
The Defense Post has been unable to review the entire video released on Thursday, January 17, but according to Nigerian journalist Ahmad Salkida who broke the news, the military base was breached with “relative ease” and houses and other structures were burned.
An extract of the video appeared to show militants looting supplies from a storage facility and multiple structures on fire. Salkida reported that military hardware and ammunition was also captured.
Rann hosts some 35,000 internally displaced people, according to the International Organization for Migration.
MSF’s emergency program manager, Hugues Robert said about 10,000 people had fled following the attack and that “structures and warehouses of humanitarian organizations have been affected.”
Robert said MSF is preparing to “assist 15,000 people with food, water and medical care” in Bodo, 7 km from Rann across the border in Cameroon.
Rann has been repeatedly attacked in the nine-year conflict and has been hit three times since March 2018.
In an attack on March 1, eight security personnel and three aid workers were killed. Three other aid workers were kidnapped, two of whom were later executed.
On December 6, Boko Haram fighters attacked a military base in Rann, but it was unclear which faction they belonged to. After an hour’s heavy fighting, the militants were pushed out with aerial support, one security source told AFP.
There have been dozens of attacks on military bases since July, most of which have been blamed on ISWA, or claimed by ISIS as ISWA attacks.
The raids are part of a wider pattern of attacks in northern Borno, which the United Nations has warned is increasingly affecting civilians.
ISWA has lately intensified its armed campaign, launching a number of major assaults on military targets in Borno and neighboring Yobe state amid signs of a takeover by more hardline leaders.
More than 27,000 people have been killed since the insurgency began in 2009, and 1.8 million people are still homeless and in need of humanitarian assistance.
Nigeria’s government and military have repeatedly insisted Boko Haram is a spent force and over the last year has encouraged internally displaced people to return.