"I wish to inform the nation that the president had suffered a stroke. However, upon being attended to by doctors his condition has been described as stable," Banda said in a statement.

Mwanawasa, 59, was rushed to a hospital on Sunday ahead of the AU summit in the Egyptian resort of Sharm el-Sheik. The summit, which opened on Monday, is expected to focus largely on the post-election crisis in Zimbabwe.

A government spokesman earlier on Monday said Mwanawasa, who had a mild stroke in 2006, remained in hospital and was being treated for high blood pressure.

A government official, who did not want to be named, said the President had appeared ill last week.

President Robert Mugabe was sworn in Zimbabwe on Sunday for a new term after a one-candidate election on Friday which observers said was scarred by violence and intimidation.

Mwanawasa, current chairman of the Southern African Development Community, has been one of the more vocal critics of the veteran Zimbabwean leader and had expressed understanding for opposition leader Morgan Tsvangirai when he pulled out of the presidential poll last week.

The Zambian leader become a favourite of the International Monetary Fund and other Western donors, who have extended billions of dollars in debt relief in the wake of his crackdown on government spending and launch of an anti-graft drive.

He became Zambia's vice president in 1991 after Frederick Chiluba ousted founding President Kenneth Kaunda in landmark multiparty elections. Mwanawasa won the presidency in 2001 and was re-elected in 2006.