The health of Zambian President Levy Mwanawasa has suddenly deteriorated, local officials have announced. Zambia's Vice-President Rupiah Banda said the president had been making steady progress until Sunday night, when he required medical intervention. Mr Banda said the president was in a serious condition but added that treatment had been successful. President Mwanawasa, 59, suffered a mild stroke at an African Union summit in Egypt, late in June. In July, Zambia's opposition called for an investigation into whether the president was fit to lead the country. The president was flown to France following his stroke, where he has remained in hospital. In a statement on Monday, quoted by Reuters news agency, Mr Banda said: "The team of doctors have reported that the intervention was successful but described the condition of His Excellency, the president, as serious." Mr Mwanawasa's health has always been an issue during his presidency. In April 2006, he suffered a minor stroke four months before general elections. Source: BBC