Abuja: Nigerian President Umaru Yar`Adua died late on Wednesday 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 -- is expected to be sworn in as head of state and 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.
The presidency announced seven days of national mourning and said Yar`Adua would be buried in his northern home state of Katsina at 2 pm (1300 GMT) on Thursday.
"The nation is in shock. The nation is mourning. The Acting President has declared seven days of mourning and during this period the Nigerian flag will fly at half mast," presidency spokesman Ima Niboro told reporters.
Information Minister Dora Akunyili said Yar`Adua had died at around 2000 GMT in the presidential villa.
US 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.
Jonathan assumed executive powers in February and has since consolidated his hold on power, appointing a new cabinet and his own team of advisers. But Yar`Adua`s death raises the stakes in the run-up to the next elections.
It is unclear if Jonathan, who is from the southern Niger Delta, will run for president because of an unwritten agreement in the ruling party that power rotates between north and south. The next four-year term is due to go to Yar`Adua`s Muslim north.