Operation OAU

Operation OAU, (May 20 – September 29, 1968), was a military conflict between Nigerian and Biafran forces in modern day south-eastern Nigeria. Operation OAU was one of the longest lasting and deadliest military operation of the entire war resulting in over 25,000 deaths combined. Although the Biafran soldiers were outnumbered more than 3 to 1 they were able to retain control of Umuahia and eventually re-capture the city of Owerri while also losing control of Aba.

Background
By late 1967 Biafra was losing more and more territory with every ongoing battle. Such cities as Enugu, Calabar, and Yenagoa had been taken by the heavily armed Nigerian soldiers and the Nigerian Airforce MiG-17 fighter jets piloted by Egyptian mercenaries. Nigerian General Murtala Mohammed began marching south from Lokoja in October 1967 on a conquest to conquer the Biafran market town of Onitsha. Mohammed managed to seize Onitsha on January 12, 1968 as well as capturing the surrounding areas after less than 24 hours of battle. The Nigerian Civil War remained in a stalemate for over 2 months before Biafran soldiers invaded and successfully captured Onitsha. With news of Onitsha's seizure Murtala Mohammed moved southward back to Onitsha escorted by a 200 man military convoy. At Abagana Biafran guerrillas lied in wait for Mohammed's convoy to arrive. Mohammed's convoy arrived at Abagana in mid-day but while they traveled down a dirt road the convoy was ambushed by the guerrillas. The guerrillas launched a homemade bomb at the convoy which resulted in a massive explosion and caused armored vehicles to flip end over end. The explosion resulted in death of nearly 150 men, 1/3 of Mohammed's convoy. The war remained in a stalemate for 2 months yet again until the Nigerian General Benjamin Adekunle invaded the Biafran city of Port Harcourt on May 19, 1968 and was able to capture the city in less than 12 hours. Murtala Mohammed met with Adekunle in Port Harcourt that same day to plan out an invasion of the Igbo heartland. Adekunle's main objective was to capture the Biafran capital of Umuahia as well as the cities of Owerri and Aba, Adekunle claimed that he and Mohammed would be able to capture the 3 cities in 3 weeks.

Aba
On May 20, 1968 Benjamin Adekunle began his invasion of the Igbo heartland. Adekunle got within 5 miles of the city until soldiers from the Biafran 12th Division led by Major Timothy Onwuatuegwu launched an attack on the invading Nigerians. The fighting between the two opposing sides remained fierce and lasted nearly 4 days before Adekunle, knowing the odds of winning were against him, decided to retreat back to Port Harcourt and draw up new plans to invade Aba. When Adekunle met with Mohammed the two decided to leave an invasion Aba for another time and attack a less defended city.

On August 1, 1968 Murtala Mohammed invaded the city without Adekunle's assistance. Unlike Adekunle, Mohammed surrounded the city and began siege. Mohammed waited tediously for the city's food supply to run out as well as constantly bombarding the city with mortars and bombs. The defending Biafrans attempted to push the Nigerians away from the city by attacking various points along the Nigerian defenses. Although the Biafrans fought as well as they could their attempts were in vein, as the city slowly starved itself until it finally succumbed to the Nigerians and surrendered on August 28.

Umuahia
After Adekunle's major defeat at Aba he wanted to reinstate the Nigerian grasp over Igboland with an invasion of the Biafran capital, Umuahia. On June 8 Adekunle reached the area surrounding Umuahia and began to set up defenses around the city to begin a siege. Before Adekunle could begin his bombardment the Biafran President Odumegwu Ojukwu fled the city in a helicopter and retreated to Owerri. The same man who fended off Adekunle at Aba, Timothy Onwuatuegwu, began attacking Adekunle's defenses with the help of guerrilla troops surrounding the city. Adekunle began to constantly launch various bombs and explosives into the city but was unable to fend off Onwuatuegwu. On June 14 Adekunle began an offensive against Onwuatuegwu by simultaneously attacking Umuahia from all sides. Adekunle was able to get within a mile of Umuahia but was pushed back by Onwuatuegwu's men. Adekunle changed his tactics and closed off all outside contact to Umuahia, no one was to be let in and no one was to be let out. After a 13 day siege Onwuatuegwu was able to escape Umuahia with about 5,000 men and retreated to Owerri which left Umuahia open to Adekunle.

On July 23, 1968 Onwuatuegwu returned to Umuahia with his men and did not hesitate to attack Adekunle's defensive positions. Adekunle was not prepared for an attack on Umuahia and his men were quickly killed off by the attacking Biafrans. Slowly but surely Onwuatuegwu pushed back Adekunle's men until Adekunle, now short of men and food, decided to retreat back to Port Harcourt for a second time on July 31.

Owerri
On September 17, 1968 Benjamin Adekunle began his third offensive against the Biafrans by beginning an invasion of Owerri. The Biafran Colonel E.A. Eutuk was put in charge, by President Ojukwu, of defending Owerri. Unlike his former invasions Adekunle was put against a rather inexperienced Colonel in contrast to the battle hardened Major Onwuatuegwu. Eutuk was overwhelmed by Adekunle's constant bombardment of the city by the Nigerian Air Force. On September 19 Ojukwu demanded Maj. Onwuatuegwu to assist Eutuk in the defense of the city. Adekunle had not the slightest idea that Onwuatuegwu and his 12th Division were on their way to Owerri. Within 2 hours of being put in command Onwuatuegwu arrived in Owerri. Adekunle's men were severely overwhelmed by the force and swiftness of Onwuatuegwu's attack. On September 20 Adekunle retreated and headed north towards Oguta. Eutuk's 16th Division pursued the retreating Nigerians through the Biafran countryside. Adekunle knew the pursing Biafrans would not let up until they reached Oguta so he contacted Nigerian soldiers in Oguta to prepare for an ambush. When the Biafrans reached Oguta Adekunle ambushed them and chased them back to Owerri. There Adekunle's men surrounded the city and began a siege. On September 29 Adekunle broke through Eutuk's defensive lines and occupied the city. Only about 500 men including Eutuk managed to escape while the remaining 2,000 soldiers were massacred by the rampaging Nigerians soldiers.

Aftermath
On October 1, 1968 Ojukwu ordered the Swedish mercenary Carl Gustaf von Rosen to bomb Nigerian defenses in and around Owerri with his squadron of Biafran pilots. Von Rosen was successful in destroying most of Adekunle's defenses allowing Biafran troop movement closer to the city. E.A. Eutuk was put in charge of attacking Adekunle and re-capturing the city. For nearly 3 months Owerri remained peaceful until December 21, 1968 when Colonel Eutuk attacked Nigerian defensive lines around Owerri. That same day Timothy Onwuatuegwu arrived in Owerri with nearly all of his available soldiers. The Nigerian General Mohammed Shuwa arrived one day later and counter-attacked Eutuk and fought a bloody battle for 18 days straight until Shuwa was pushed back on January 8, 1969. Four days later Benjamin Adekunle ordered his soldiers to attack the Biafran troops within city boundaries. The Biafrans were pushed out of the city for 3 days but they managed to re-take the city after Adekunle's men were bombed out by Von Rosen's air squadron. Due to Adekunle's constant defeats at the hands of the Biafrans the Nigerian President Yakubu Gowon replaced him with General Shuwa in leading the attack against the defending Biafrans. On April 1, 1969 Biafran soldiers began an offensive against the inexperienced Shuwa. On April 19 Eutuk managed to surround Shuwa's remaining soldiers and keep them at bay for 6 days. Shuwa eventually fought his way out of Owerri and retreated to Port Harcourt.