Nigerian president vowed to address grievances but insisted army crackdown would continue.
'We are all one and the law must take its course,' said president Abdel Fattah al-Sisis in televised statement.
Verdict marks end of 16 year struggle for justice by victims and rights groups.
'Africa's Pinochet' is said to have received US and France backing during his brutal rule.
Five UN peacekeepers were killed and 1 seriously injured in a terror attack on the day that is observed to honour them.
The Republic of Biafra was established on 30 May 1967, triggering a war that caused the death of millions.
Group condemns perceived marginalisation in Niger Delta and demands greater shares of oil revenues.
At least 3,000 people were killed in post-election violence in 2010.
Buhari promised he would end corruption and terrorism and revitalise crippled economy.
Tens of thousands of Zimbabweans took part in ruling party's Million Man March in Harare
Incident comes on the heels of African diplomatic community's protest against rising racism.
Zimbabwe's underfunded prisons have been hit by food shortages and inmate deaths.
The debris was described as being similar in appearance to other previously recovered pieces of wreckage.
The Expropriation Bill will provide compulsory land ownership for black people in the country.
Libyan authorities expected to request help from UK 'fairly swiftly' to help stop people and arms smuggling.