Muhammadu Buhari sworn in as president of Nigeria

File photo of Nigeria's President-elect Muhammadu Buhari addresses the media during former British Prime Minister Tony Blair's visit at the Defence House in Abuja, Nigeria, May 13, 2015. REUTERS/Afolabi Sotunde

ABUJA (Reuters) - Former military ruler Muhammadu Buhari was sworn in as President of Nigeria on Friday at a ceremony in the capital attended by numerous African heads of state and foreign dignitaries including U.S. Secretary of State John Kerry. Buhari, dressed in traditional Muslim attire, stood on the stage clutching a Koran in his right hand, as he pledged to uphold the constitution and laws of Africa's most populous nation. (Reporting by Julia Payne; Editing by Ed Cropley)