Joyce Banda was sworn in today as president of Malawi, succeeding Bingu wa Mutharika who died on Thursday in the southern African nation. Ms Banda (61), had been serving as vice-president under Mr Mutharika and takes over under the terms of the constitution.
She becomes the first female head of state in southern Africa.
The government only officially confirmed 78-year-old Mr Mutharika's death earlier today, two days after he had died following a heart attack.
His body had been flown to a military hospital in South Africa.
The delay in the announcement had raised worries about a political crisis because Ms Banda had been expelled from Mr Mutharika's ruling DPP party in 2010 after an argument about the succession, though she retained her state position.
Ms Banda (61), who will be southern Africa's first female head of state, appeared at a news conference in the capital Lilongwe to declare 10 days of official mourning for Mr Mutharika, who had ruled for eight years. She ordered national flags to be flown at half-mast and the state broadcaster to play sombre music.
"I call upon all Malawians to remain calm and to keep the peace during this time of bereavement," Mr Banda said, flanked by members of the cabinet, the attorney general and the heads of the army and the police.
Asked by a reporter whether she was assuming the presidency, Ms Banda, a women's rights activist, replied: "As you can see, the constitution prevails".
The constitution stipulates that the vice president takes over if the president dies, but Mr Mutharika appeared to have been grooming his brother Peter, the foreign minister, as his de facto successor.
Ms Banda is expected to run the country until scheduled elections take place in 2014.
The presidency and cabinet issued a statement assuring citizens and the international community "that the constitution of the Republic of Malawi will be strictly adhered to in managing the transition."
Both Britain and the United States, which had been major donors to Malawi until they froze millions of dollars in aid over rows with Mr Mutharika over his policies and actions, urged a smooth transition respecting the constitution.
"We trust that the vice president (Banda) who is next in line will be sworn in shortly," the US State Department said.
British foreign minister William Hague said in a statement: "I urge all sides to remain calm and (hope) that a peaceful handover takes place as provided for under Malawi's constitution."
The streets of the capital Lilongwe and the main commercial city Blantyre were calm today, though police guarded strategic locations.
There appeared to be little public sorrow at Mr Mutharika's death. Many of Malawi's 13 million people had viewed him as an autocrat personally responsible for an economic crisis that stemmed ultimately from a diplomatic row with former colonial power Britain a year ago.
Britain and others froze aid worth some 40 percent of government spending, fuel supplies dried up and food prices soared, leading to popular unrest and attacks on Mr Mutharika's economic policies by bodies as diverse as the Catholic Church and the International Monetary Fund.
"It's sad that he is leaving behind so many unsolved problems, which will be difficult to tackle even by the vice president or whoever takes charge," said Stella Mataka, a waiter at a lodge near Blantyre's Chileka International airport.
As reports of the death of the self-styled 'Economist in chief' swept the capital, there were bursts of drunken jubilation among those who accused Mr Mutharika of turning back the clock on 18 years of democracy in the 'Warm Heart of Africa'.
Medical sources said Mr 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.
"We as government will be in consultation with the bereaved family, advise the date when our president's body will arrive from South Africa and other funeral arrangements," Ms Banda said.
"I also want to ask all Malawians to join me in wishing that the soul of our president rests in peace," she added.
President Michael D Higgins extended condolences to Ms Banda and the people of Malawi on the death of Mr Mutharika.
He said Ireland remained committed to working in partnership with the government and people of Malawi "in our shared objective of enhancing the economic and social wellbeing of all the citizens of Malawi".
"Ireland will continue to focus specifically on improving national and household food security and nutrition, sectors in which the late president had a particular interest and in which he made such a positive contribution," Mr Higgins said in a statement.
Reuters