Zambian President Levy Mwanawasa speaks at the University of Arkansas's school of public service last September. (Mike Wintroath/Associated Press)

Zambian President Levy Mwanawasa, who was among the first African leaders to voice criticism of Zimbabwe's autocratic leader, died Tuesday in a hospital in France. He was 59.

Mwanawasa had been being treated in Paris since suffering a stroke six weeks ago.

Zambia's vice-president, Rupiah Banda, announced Mwanawasa's death Tuesday and declared a national week of mourning.

"It is with deep sorrow that I have to tell the people of Zambia that our president … has passed away this morning," he said on radio and television.

The Zambian leader had a reputation for fighting corruption in his country and speaking out against Zimbabwean President Robert Mugabe, who has long been seen as an independence hero on the continent.

Zimbabwe's opposition leader Morgan Tsvangirai remembered the Zambian leader as a "good friend and comrade" who stood up for democracy in southern Africa.

"His passing-on is a sad day to the Zimbabwean people," said Tsvangirai, who had asked repeatedly for Mwanawasa to mediate Zimbabwe's political crisis.

3rd president since independence

French President Nicolas Sarkozy called Mwanawasa's death "a great loss for the African continent" and democracy.

Mwanawasa was Zambia's third president since independence from Britain in 1964. He practised law before entering government service as a solicitor general in 1986 under the country's first president.

In 1991, he was appointed vice-president under the second president, Frederick Chiluba, but quit the post, complaining of corruption.

Despite that, Chiluba later tapped him as his successor, and Mwanawasa won the presidency in 2001 in an election marred by allegations of fraud.

During Mwanawasa's time in office, he pursued economic and anti-corruption reforms and targeted Chiluba, who was later found guilty in a London court of stealing $46 million from state coffers during his decade of rule. Mwanawasa was re-elected in 2006 in a poll generally seen as fair and transparent.

Death leaves power vacuum

Mwanawasa was praised by Zambians and many Western investors and donors for his free-market policies and high-profile anti-graft campaign, though he failed to bring the country out of crushing poverty.

The leader of Zambia’s main opposition Patriotic Front party, Michael Sata, has gained support in Zambia's sprawling townships, where many of the country's urban poor live.

Riots broke out briefly after 2006 elections when Sata supporters accused the electoral commission of manipulating the results.

Mwanawasa's death leaves a power vacuum in Zambia. Under the constitution, an election should be held within 90 days.

With files from the Associated Press