The siege of Owerri, (October 15, 1968 – April 25, 1969), was a military conflict between Nigerian and Biafran forces. The capture was a major victory for the Biafrans because the victory opened up telephone lines, enhanced road telecommunications, and showed that with stiff resistance, Biafra could defeat Nigerian forces.
Prelude
In July 1968, commander of the 3rd Marine Commando (3MCDO), Colonel Benjamin Adekunle began making plans for an invasion of Aba, Owerri, and Umuahia in a military operation he nicknamed Operation OAU. Adekunle stated that he would be able to capture all three cities in two weeks. Adekunle's strategy was to surround a city and starve it into submission before attacking its weakened defenders. After 12 days of violent fighting in Aba, the 3MCDO managed to capture the city on September 14, followed by Owerri on September 16. When the 3MCDO was pushed back at Umuahia, the Nigerians retreated to Owerri, where they set up defenses in and around the city. The Biafrans made their way down the Aba-Umuahia road and managed to capture the entire road along with Aba on October 15.
The siege
On 15 October 1968, while Nigerian Head of State Yakubu Gowon was distracted by the anti-tax riots in the west, the Biafran Brigadier Alexander Madiebo encircled Owerri while a unit of Biafran soldiers attacked Nigerian supply convoys attempting to enter the city. The Biafrans were assisted by heavy rain and mud which slowed down supply convoys even further.
On 3 December the Biafran 14th Division under Colonel Ogbugo Kalu and 63rd Brigade under Col. Lambert Ihenacho moved towards Owerri, capturing the villages of Eziama and Elelem.
On 5 December the Biafran 60th Brigade under Colonel Azum Asoya began the main assault on Owerri, in which over 50,000 rounds of ammunition, 300 mortars, 200 howitzer shells, and 20 anti-tank weapons were fired. The assault lasted for two days but the 3,000-man Nigerian 16th Division under Colonel E. A. Etuk stayed in their original position, while suffering heavy casualties. The Biafran 68th Battalion under Major Ikeji gained control of a stretch of the Port Harcourt road from Owerri to the Otamiri River, establishing a link with the 63rd Brigade.
On 19 December 16 Division regrouped its soldiers and captured the town of Abiaka, followed by Avu and Afrola on 29 December.
On 6 January 1969 the Biafran 60th Brigade captured Umuakpu, Umuagwo, and Omanelu while the Biafran 68th Battalion under Major Ikeji seized Obinze; the 68th Battalion attempted to capture Avu but were beaten back by the Nigerian 16th Brigade. By the end of the day, the Biafrans controlled much of the Port Harcourt road and began planting mines, digging ditches, and laying trees across it in an attempt to block any Nigerian reinforcements from entering Owerri.
On 15 January the Biafran 60th Brigade attacked Owerri and were able to force the 16th Division to retreat across the Otamini Bridge. Instead of pursuing the retreating Nigerians, the hungry and half-naked Biafran soldiers discovered the Nigerians' food and clothing supplies and decided to have their fill. The Nigerian 16th Brigade was able to regroup and made a counter-attack across the Otamini Bridge, causing the Biafrans to retreat.
On 24 January the Nigerian government renewed its offensive and began bombing Biafran positions in the area. After five days of continuous air strikes, the Biafrans remained in their original positions; the Nigerian government knew that Owerri was encircled and they couldn't do anything about it.
On 7 February both the Nigerian Air Force and Egyptian mercenaries bombed out and completely destroyed the villages of Umohiagu and Ozu Abam, which prompted accusations of deliberately targeting civilians. The government ordered the Nigerian Air Force to avoid civilian targets but they disregarded this request and continued to bomb towns and Red Cross shelters. In late February, Gen. Gowon visited the 16th Brigade in Owerri and attempted to encourage them to keep fighting until re-enforcements could be sent.
On 14 March Nigerian troops attempted to capture the Omanelu-Umuakpu and Elele-Ubimini-Awarra roads but were beaten back by defending Biafran soldiers, leaving them isolated and short of food.