ABUJA (Reuters) -- Nigerian President Umaru Yar'Adua died late on May 5, aged 58, after a long battle with kidney and heart ailments, paving the way for the most hotly contested succession since the country's return to democracy a decade ago.
Acting President Goodluck Jonathan -- who has been running Africa's most populous nation for months during Yar'Adua's illness -- was sworn in today as head of state and is expected soon to appoint a new deputy, according to the constitution.
The pair will then complete the unexpired presidential term in the oil-producing nation of more than 140 million people until elections due by April 2011.
"Nigeria has lost the jewel on its crown," Jonathan said, announcing seven days of national mourning.
Yar'Adua will be buried in his northern home town of Katsina today.
U.S. President Barack Obama said his thoughts and prayers were with Yar'Adua's family and remembered his "profound personal decency and integrity."
Yar'Adua had been absent from the political scene since November, when he left for medical treatment for a heart condition in Saudi Arabia. He returned to Nigeria in February but remained too sick to govern.