The invasion began on August 9 when 3,000 Biafran soldiers led by General Victor Banjo crossed the River Niger Bridge into Asaba.

However, it was cripplingly delayed due to arguments between Ojukwu and Victor Banjo on whom to appoint as governor of the Mid-West, giving Gowon enough time to assemble a defensive line in the west.

In a large pincer movement, another Nigerian force headed south from Auchi towards Benin, as Benjamin Adekunle's 3rd Marine Commando division landed at Warri and promptly took Ughelli and Sapele.

This was disagreed upon by many Midwestern Igbo officers, who believed the confederate and secessionist proposals by the other regions were a better approach to the issue, but this was dismissed by Ejoor and his cabinet.

Even so, differences in the interpretation in these accords led to an even greater divide between Ojukwu and the Federal Government, later leading to Biafra's declaration of independence on May 30, 1967.

"[5] Traffic across the Niger River Bridge was halted and the Midwest government abided by the federal authorities' imposition of an embargo on Biafra, though some trade among civilians persisted through cross-river activities.

After a mission to recapture Nsukka on July 30 failed and resulted in death of Major Kaduna Nzeogwu, Ojukwu began drawing up plans for an invasion of Nigeria's Mid-Western Region in an attempt to divert attention away from Enugu, as well as to perhaps bring a quick end to the war.

At 3 a.m. On August 9, 1967 after a signal was given, a 3000 strong mobilized rifle brigade of Biafran soldiers under General Victor Banjo crossed the River Niger Bridge at Onitsha and entered Asaba, the core of what was to be the 101st division, dubbed the "Liberation Army of Nigeria" and "Midwest Expeditionary Force" with Lt. Col Emmanuel Ifeajuna as its Chief of Staff, and Joe Isichie as its quartermaster general.

[citation needed] Banjo announced over Benin Radio that the incursion was "designed to insulate the people of the Midwest from the coercive threats of Northern military presence".

[8] The Biafrans encountered minimal opposition in Asaba due to the collusion of several Igbo officers in the Midwest Army garrison, some of whom then defected.

[9] According to British journalist Frederick Forsyth, who was trailing the Biafran column, the "two dozen or so" Nigeran troops defending the bridge were "swept aside".

The 12th Battalion was transformed into the 12th Brigade and given the job of quickly capturing Ibadan and Lagos from two axes at the towns of Ore and Okitipupa but this was postponed for three days while President Ojukwu and General Banjo argued over whom to appoint Governor/Administrator of the Mid-Western Region.

When General Banjo returned to Benin City on August 12 he resumed the extremely delayed advance of the 12th Brigade to make its way to the town of Ore but not to attack Ibadan or Lagos until further notice.

[11] After being appointed as Governor of the Midwest on August 17, Okonkwo the same day installed a dusk to dawn curfew in which only citizens with passes would be allowed to move freely at night, along with other measures equivalent to martial law.

Non-Igbo citizens, especially the Hausa community, were subject to harassment, assault, and murder from Biafran soldiers while women were often molested and sometimes raped, in retaliation for the 1966 anti-Igbo pogrom.

Because of a series of uprisings against the occupying Biafrans in Benin City, General Okonkwo began raising a force of loyal native inhabitants to combat the rebels.

Due to these rebellions Biafran soldiers began raiding and pillaging villages throughout both the Mid-Western Region and Niger Delta inhabited by anyone other than Igbo civilians.

[15] The loss of the Midwest and a minor aerial attack on Lagos by a Biafran bomber stoked panic among federal authorities[16] and led Gowon to declare a policy of "total war" against Biafra.

[17] The federal government quickly organised the Nigerian 2nd Division with some trained soldiers, veterans, support forces, prisoners, and large numbers of untrained volunteers and placed it under the command of Colonel Murtala Muhammed.

Most Biafran soldiers trapped behind enemy lines abandoned their uniforms and weapons before integrating into the local communities, escaping eastward when they had the chance.

To support federal ground operations in the Midwest, the Nigerian Navy redeployed some of its ships from the Bonny area to the mouth of the Escravos River, where sailors outfitted several Gulf Oil rigs with anti-aircraft guns.

[23] On September 25, Biafran forces attempted to take advantage of the navy's focus on the Midwest by launching Operation Sea Jack against the federal garrison in Bonny.

The following afternoon, federal forces under Colonel Ike Omar Sanda Nwachukwu passed through Asaba and secured the western landing of the Niger River Bridge.

[29] Gowon instructed Colonel Muhammed to refrain from crossing the bridge at that time, fearing an immediate attempt to do so would frighten the Biafrans into blowing it up.

[31] According to historian Max Siollun, the invasion "was a disastrous political miscalculation by Biafra" that eliminated what sympathy the secessionist state had in the Midwest and Western regions and led some Nigerians to conclude that it not only wanted to defend itself but sought to expand its territory.

[32] Historian S. E. Orobator, arguing that the invasion failed to severely hamper federal advances into Biafran territory, caused infighting in Biafra's military leadership, and dissipated popular sympathy for the secession in the Midwest[33] concluded that "In sum, Biafra would have benefited more from the Midwest had she maintained the existing relationship, instead of embarking on an invasion which eventually mutilated against her over-all interests" and "will go down on record [...] as one of the most severe strategic blunders in contemporary wars of secession.