LAGOS (Reuters) - Nigeria’s air force on Tuesday said it was deploying aircraft to the southeast of the country where unrest related to a campaign for secession has escalated in an area formerly known as Biafra.

The military presence in the southeast has increased in the last few weeks as part of an operation that the military said was part of efforts to crack down on crime, kidnapping and secessionist agitation. The air force deployment marks a further escalation of the operation, which began this month.

“The essence of the deployment is to provide the necessary air cover to the ground troops to enhance overall operational cohesion and efficiency,” said Olatokunbo Adesanya, a Nigerian Air Force (NAF) spokesman.

“The request by the Nigerian Army for close air support made the involvement of the NAF inevitable,” he added.

The military deployment has led to tension between troops and the Indigenous People of Biafra (IPOB) secessionist group which last week accused soldiers of laying siege to their leader’s home. The army denied the accusation.

A curfew was subsequently imposed in Abia state, where the residence is located, and the army on Friday categorized IPOB as a “terrorist organization”.

Secessionist sentiment has simmered in the southeast since the Biafra separatist rebellion plunged Africa’s most populous country into a civil war from 1967 to 1970 that killed around one million people.