Zambian President Levy Mwanawasa died in a French hospital aged 59, nearly two months after he was hospitalised for a stroke, the country's vice president said.
"It is with deep sorrow that I have to tell the people of Zambia that our president ... has passed away this morning," Vice President Rupiah Banda said on radio and television. He announced a weeklong period of national mourning.
Banda did not give the cause of death. But he said that Mwanawasa had taken a turn for the worse.
The president was evacuated to Percy Military Hospital in Paris after he collapsed on June 30 on the eve of an African Union summit in Egypt.
French President Nicolas Sarkozy called Mwanawasa's death "a great loss for the African continent" and for democracy.
Mwanawasa won praise for his anti-corruption and economic modernisation drive in one of the world's biggest copper producers but failed to lift the Zambian people out of crushing poverty.
He broke the traditional silence of African leaders toward his autocratic neighbour, Zimbabwe's Robert Mugabe. Mwanawasa described Zimbabwe as a "catastrophe," and criticised the trampling of democracy in the 2008 presidential elections.
Mwanawasa's stance encouraged other African presidents to show their displeasure with Mugabe, who was long revered as an African independence hero.
The softly spoken lawyer was Zambia's third president since independence from Britain in 1964 and so was not bound by the liberation movement ties of older African leaders.
His death leaves a power vacuum in Zambia. Under the country's constitution, elections are meant to be held within 90 days.