http://www.bbc.co.uk/news/world-africa-17643602Mr Mutharika, 78, suffered a cardiac arrest on Thursday and state media said he was being treated in South Africa.Medical and government officials said on Friday that he was dead but there was no formal announcement, leading to fears of a power-struggle.
A government official said on state radio that there would be 10 days of national mourning.
"We are sad to announce that the President of Malawi, Bingu wa Mutharika, has died," Bright Msaka, secretary to the president and cabinet, said in a statement carried by state radio.
"The Milpark Hospital in South Africa has also confirmed his death," Mr Msaka said. "There will be 10 days of national mourning, and the constitution will be adhered to in managing the transition."
Continue reading the main story
The delay in announcing Mr Mutharika's death had sparked speculation that Mr Mutharika's allies might try to prevent the vice-president from taking over, as stipulated by the constitution.
At a news conference held within hours of the official confirmation of Mr Mutharika's death, Vice-President Joyce Banda also said the constitution would be followed, but she held back from saying directly if she would be taking over as interim president.
"I don't think there's any way we can discuss who is caretaker and who is not," she said. "The constitution is prevailing right now."
AFP news agency said the head of the army, the chief of the national police, the attorney general, and several cabinet ministers and MPs were standing near her as she spoke.
"The paramount issue to be discussed at the cabinet meeting is on the funeral of the father of the nation," she said. "In the meantime, I call upon all Malawians to remain calm and to keep the peace during this time of bereavement."
Vice-President Banda fell out with Mr Mutharika in 2010 over the succession and she was expelled from the ruling Democratic People's Party (DPP).
The president's brother, Foreign Minister Peter Mutharika, was lined up to be the DPP's presidential candidate in the 2014 elections.
Both the UK and the US have called on Malawi to respect the constitution.
Mr Mutharika governed Malawi for eight years, but was recently accused of mismanaging the economy and becoming increasingly autocratic.
He fell out last year with former colonial ruler Britain, which withdrew its direct aid, accusing the Malawian government of mishandling the economy and of failing to uphold human rights.
Malawi is one of the poorest countries in the world, with an estimated 75% of the population living on less than $1 (60p) a day.
The country has suffered shortages of fuel and foreign currency since the UK and other donors cancelled aid.
That was close
For a second there we could have lost Obama too