Medical sources say Malawian President Bingu wa Mutharika has died after suffering a heart attack, but there has been no official announcement of his death.

Diplomatic sources say he collapsed after taking ill at his home in Lilongwe, the capital, on Thursday.

He was rushed to the hospital, where sources say he died.

Mr. Mutharika was elected president of Malawi in 2004 and won a second term in 2009.

He was credited with improving food security in Malawi and with making his country a political and economic model for other African countries.

But in more recent years, the economy has stumbled and unemployment has been high. Critics of the president say he had become increasingly autocratic. Nineteen people were killed last July in anti-government protests.

An economist by education, Mr. Mutharika was a World Bank official and served as a civil servant in Malawi. He was appointed minister of economic planning and development in 2002 and then-President Bakili Muluzi nominated him as his successor. Mr. Mutharika was the head of the ruling Democratic Progressive Party, which has the majority in parliament.