Bongo, whose every move has been scrutinised for signs of ill health, attended commemorations on the eve of the country's anniversary of independence.

It was the first time he had been seen in public outside the presidential palace since falling ill last October, except for appearances that were filmed and edited by Gabonese government or state media.

Smiling, the 60-year-old head of state exchanged a few words with security officers before laying a wreath at the tomb of Gabon's first president, Leon Mba.

Bongo walked with a stick and an aide helped him to climb several steps. The ceremony lasted half an hour, which was shorter than in previous years.

Speculation about Bongo's ability to rule the small oil-rich country surged after he suffered a stroke while in Saudi Arabia last October.

Ten members of Gabon's political opposition, civil society and trade union movement have filed a suit requesting Bongo be assessed to see whether he is medically fit to continue in office.

A lower court dismissed the case in May, saying that only the two houses of parliament, or the Constitutional Court acting at the behest of the government, were empowered to determine whether the president was unfit.

But the Court of Appeal on Monday said it would hear an appeal by the plaintiffs and set a date for it -- August 26.

Bongo is scheduled to make a televised speech on Friday evening and on Saturday attend an annual military parade to mark the country's independence from France in 1960.

Opposition figures have urged the public to turn out in large numbers on Saturday to gain a closer look at his health.

Bongo succeeded his father Omar Bongo, who became head of state in 1967 and died in June 2009, leaving a legacy of corruption allegations.