Sudanese president Omar al-Bashir has left Nigeria after human rights lawyers and civil rights activists demanded his arrest, a Sudanese diplomat has said.
The diplomat denied that al-Bashir's hasty departure was related to demands for his arrest. Human rights lawyers filed a lawsuit to try to compel the government to detain him and surrender him to the International Criminal Court for trial.
Presidential spokesman Reuben Abati said al-Bashir had come to attend the summit, and not at Nigeria's invitation. He said the African Union told its 53 member states not to co-operate with the European-based court that some accuse of targeting Africans.
Human rights lawyers filed a suit in the Federal High Court to try to compel Nigeria's government to arrest al-Bashir, and a civil rights group urgently appealed to the International Criminal Court to refer the government to the United Nations Security Council for allowing the visit.
The ICC belatedly demanded that Nigeria "immediately arrest" the fugitive. It noted that it could refer the Nigerian government to the UN Security Council for failing to execute an order of the court, of which it is a member.
A statement said the court has issued two arrest warrants for al-Bashir, in 2009 and 2010, to stand trial for five counts of crimes against humanity, two counts of war crimes and three counts of genocide against the Fur, Masalit and Zagawa tribes in Darfur.
The US Embassy criticised Nigeria's decision to welcome an indicted criminal, and the UK expressed its "disappointment".
Nigeria was forced in the past to hand over an internationally wanted criminal - former Liberian president Charles Taylor, the warlord who began that country's devastating civil war in 1989.
In 2003, Taylor resigned under pressure and a promise from Nigeria's government to give him a safe haven. When democratically elected leader Ellen Johnson Sirleaf demanded his extradition in 2006, Nigeria came under huge international pressure and was forced to go back on its word and hand him over.