Malawi's President Bingu wa Mutharika has died after a heart attack, doctors who treated him said Friday, as the troubled and impoverished southern African nation awaited official word of Mutharika's death and who would succeed him, AP reported. The doctors, who spoke on condition of anonymity because they were not authorized to speak to reporters, said the 78-year-old died Thursday, and his body was then flown to South Africa. Malawi's government has so far issued only a brief statement on state radio and television, saying Mutharika was taken ill and was flown to South Africa for further treatment. A Cabinet minister, speaking on condition of anonymity because the matter is sensitive, said announcing the death required taking political steps. He did not elaborate, but questions over succession are likely complicating matters. Under the constitution, Vice President Joyce Banda, 62, should take over to complete his term, due to end in early 2014. But Banda has clashed with Mutharika. She was expelled from his party and formed her own. She remained vice president. Mutharika's death will likely mean another period of political turmoil. Mutharika's brother, Foreign Affairs Minister Peter Arthur Mutharika, may try to challenge Banda for leadership, though the constitution appears clear that the vice president should take over. Mutharika's predecessor and former mentor Bakili Muluzi decried the official silence on his death and on the nation's political future. -- SPA