LAGOS, Nigeria (AP) -- An Islamic State-linked extremist group blamed for killing thousands in Nigeria and neighboring West African countries has killed four members of the Nigerian army, including a general, the army said Saturday.
The Islamic State in West Africa Province (ISWAP) killed the security personnel during an attack in the Askira Uba area of Borno state, where a war against a rebel insurgency has been centered for more than a decade.
A Nigerian army spokesperson said its troops killed "several" ISWAP members in response to the attack, which residents told The Associated Press had also targeted a military base and unfolded over three days.
Hassan Chibok, a community leader in the neighboring Chibok council, said a classroom building and other structures were destroyed by the extremist insurgents.
"The primary school (in Askira Uba) was burned down. The primary healthcare center was also burned down, and the house of the village head," he said.
"In the fierce encounter, which is still raging at the time of filing this report, troops supported by the air component of OPHK (Operation HADIN KAI, the code name for the military operation in the northeast) have destroyed five A-Jet, two A-29, two dragon combat vehicles and nine gun trucks," the army's spokesperson, Brigadier General Onyema Nwachukwu, said in a statement.
The development is yet another sign that the IS-linked group remains a threat in the northeastern part of Africa's most populous country despite the Nigerian military's repeated claims of successes in the war against insurgency especially after ISWAP lost two leaders in the last few months.
ISWAP split from Boko Haram in 2016. The rival extremist groups remain united in an insurgency against the Nigerian government that has expanded to neighboring Niger, Chad and Cameroon.
Militants in the IS-linked group have sought to consolidate their position in the Lake Chad basin and northeast Nigeria following the death of Boko Haram leader Abubakar Shekau.
Despite losing two of its leaders - Abu Musab al-Barnawi and successor Malam Bako -- in the last few months, ISWAP continues to target the Nigerian military and those who aid soldiers.