Malawi's state radio announced on Saturday that President Bingu wa Mutharika had died, and Vice-president Joyce Banda prepared to take over as southern Africa's first female head of state.
The radio announcement confirmed reports by medical and government sources on Friday that the 78-year-old Mutharika had died shortly after a heart attack the previous day.
The delay in the official announcement, as well as the airflifting of Mutharika's body to South Africa on Thursday, had aroused suspicions about the succession process in the impoverished southern African nation.
The United States, which has been an important aid donor for Malawi, expressed alarm at the official silence and said it did not want to see any delay in the swearing of Banda, a women's rights activist.
Malawi's constitution is clear that Banda should take over, although a smooth transition has not been completely assured since she was booted out of Mutharika's ruling DPP party in 2010 after an argument about succession.
Mutharika appeared to have been grooming his brother Peter, the foreign minister, as his de facto successor.
Malawi's constitution lays out a clear path for succession and we expect it to be observed. We are concerned about the delay in the transfer of power, the U.S. State Department said in a statement.
We trust that the vice president who is next in line will be sworn in shortly.
Banda is due to hold a news conference on Saturday, officials said, as well as meet the Attorney General and head of the armed forces, suggesting any divisions over the transfer of power have been ironed out.
Few of Malawi's 13 million people mourned Mutharika, whom they regarded as an autocrat personally responsible for an economic crisis that stemmed ultimately from a diplomatic spat with former colonial power Britain a year ago.
We know he is dead and unfortunately he died at a local, poor hospital which he never cared about - no drugs, no power, said Chimwemwe Phiri, a Lilongwe businessman waiting in a line of cars for fuel at a petrol station.
As reports of the death of the self-styled Economist in chief swept the capital, there were pockets of drunken jubilation among those who accused Mutharika of turning back the clock on 18 years of democracy in the Warm Heart of Africa.
I am yet to see anyone shedding a tear for Bingu, said Martin Mlenga, another businessman. We all wished him dead, sorry to say that.
Medical sources said Mutharika's body was flown to South Africa because Malawi's energy crisis was so severe the Lilongwe state hospital would have been unable to conduct a proper autopsy or even keep his body refrigerated.
There has been no comment from the South African authorities.
(Reporting by Mabvuto Banda; Editing by Ed Cropley and Pascal Fletcher)