The Nigerian Air Force has deployed aircraft to the country's south-east to support the army in its so-called Operation Python Dance in the region.
The military says the operation is aimed at combating kidnapping and other criminal activity, but troops engaged in several deadly clashes with separatists in the area last week, resulting in widespread tension across the country.
The air force has now joined in the operation to provide air cover to ground troops.
The leader of the Pro-Biafran secessionist movement, Nnamdi Kanu, has not been seen since the military raided his house last week in the city of Umuahia.
The Nigerian army had labelled the separatists group, the Indigenous People of Biafra (IPOB), a terrorist organisation, but later retracted the statement.