US President Donald Trump says American and Nigerian forces have killed the second-in-command leader of ISIS globally.
Mr Trump said Abu-Bilal al-Minuki was "eliminated" after sources found him in hiding in Africa.
"Tonight, at my direction, brave American forces and the armed forces of Nigeria flawlessly executed a meticulously planned and very complex mission to eliminate the most active terrorist in the world from the battlefield," he wrote in a post on social media.
"Abu-Bilal al-Minuki, second in command of ISIS globally, thought he could hide in Africa, but little did he know we had sources who kept us informed on what he was doing.
"He will no longer terrorize the people of Africa, or help plan operations to target Americans."
He also thanked the Nigerian government for its partnership in the operation.
The Islamic State extremist group did not comment on the claim.
Nigeria had come under scrutiny from Mr Trump, who had said that Christians there were being persecuted, which the African nation's government denies.
The US had struck what it said were Islamist bases in north-western Nigeria on Christmas Day last year, following Mr Trump's accusations.