In the mid-1960s, there was a military coup led by Major Nzeogwu that overthrew the democratic government which had lost credibility due to rigged elections and ensuing violence.

[1] The capture of Calabar and other coastal cities by October 1967 left Port Harcourt's airport the only means of international communication and travel for Biafra, though the Biafrans in turn spent time devising other ad hoc air strips out of old roadways.

With the Biafrans in retreat, the Nigerian 15th Brigade under Col. Ipoola Alani Akinrinade stationed at Bonny launched an attack on Port Harcourt.

During five days of heavy fighting, Port Harcourt's airport and army barracks changed hands on numerous occasions but by May 24 most Biafran troops had been pushed out of the city into the surrounding areas.

[5] Nigerian forces also gained control of the city's airport, which was used as a forward base to stage air raids into Biafra's interior.

A large segment of the Igbo population of the city fled in advance of its capture by federal forces into the Biafran interior, abandoning their homes and valuables.

[8] Many Ijaw people welcomed the arrival of the federal troops and lay claim to some of vacated properties and filled local leadership positions.

This proved difficult in Port Harcourt, as the Rivers State government defied federal authorities and refused to evict squatters on Igbo properties.