January 26, 1968 – War reaches a stalemate, with neither side able to make major gains

Nearly six months after the beginning of the Nigeria-Biafra war, the opposing forces had largely reached a stalemate because neither the Nigerians nor the Biafrans were able to make and sustain significant advances. Despite the fact that by the end of 1967 the Nigerians had surrounded the Biafrans and cut off the majority of their supply lines, the Biafrans continued to resist surrender and kept on fighting. 

Numerous actors in the international community believed that the war would be a quick victory for the Nigerians, so after a prolonged stalemate, some actors began changing their tactics. US President Johnson declared an arms embargo against the FMG of Nigeria, while the French continued to supply arms to Biafra and Great Britain continued to sell arms to the Nigerians. However, as the stalemated war progressed, the famine and humanitarian disaster occurring within Biafra frequently made international headlines, thus leading to an influx of humanitarian organizations within Biafra itself. The war did not end until January 1970.  

see also:

Article: Secessionist Biafra is Surviving Blockade

Book: The Biafran War: The Struggle for Modern Nigeria