The president will be sworn in for a second term on Friday
Malawi's President Bingu wa Mutharika has won a second five-year term in office, according to the country's electoral commission.
The commission said that he had won 2.7 million votes, with his nearest rival John Tembo winning 1.2 million.
Mr Tembo has alleged that there was election fraud.
The new president is due to be inaugurated on Friday, and several regional leaders are already in Malawi to attend the swearing-in ceremony.
"I declare Bingu wa Mutharika, president of the DPP (Democratic Progressive Party), winner of 2009 presidential elections," said commission head Anastacia Msosa.
The result was declared after 93% of polling stations had submitted their figures.
Mr Mutharika, a 75-year-old former World Bank official, saw his DPP taking a clear lead in parliamentary elections as well.
Partial official results have the DPP winning 59 of the 193 seats; Mr Tembo's Malawi Congress Party (MCP) 17; Bakili Muluzi's United Democratic Front (UDF) 10; and the Malawi Forum for Unity and Development just one. Eleven seats have gone to independents.
Mr Muluzi was barred last Saturday from seeking a third term and his UDF instead backed Mr Tembo.
Mr Muluzi told Malawian media: "As a former president of this country, I'm saying: 'Let's move forward.'
"I telephoned him [Mr Mutharika] this morning, we had a conversation and I conveyed my congratulations to him for the victory and wished him well and his DPP party."
But on Wednesday, the MCP disputed results in its traditional stronghold of Central Province, saying its poll agents had been denied access to counting centres in the area.
International poll observers said the president had enjoyed an unfair advantage, including a partisan state media.
EU observer group head Luisa Morgantini said the Malawi Broadcasting Corporation and Television Malawi had failed to provide balanced coverage of the campaign.
Former Ghanaian President John Kufuor, leader of the Commonwealth observer team, said: "We are extremely concerned at the conduct of state-owned media in its coverage of these elections."
The election followed a five-year feud between Mr Mutharika and his predecessor Mr Muluzi that brought a failed impeachment bid, parliamentary deadlock and coup plot claims.
Mr Mutharika was elected on a UDF ticket in 2004 but he then fell out with Mr Muluzi, accusing his one-time backer of trying to stonewall an anti-corruption drive.
The president quit his rival's party in 2005 to form the DPP and lead a minority government.
Poverty, agriculture and health care are the big issues for Malawi, where two-thirds of the 13 million population lives on less than $1 a day and Aids has orphaned an estimated one million children.
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