A Gabonese opposition party on Tuesday accused the government of peddling a "lie" over the health of President Ali Bongo after he was hospitalised in Saudi Arabia nearly three weeks ago.
"A group of people within the president's office has opted for evasiveness, duplicity and even (for telling) a state lie," the National Union party said in a statement.
President Bongo, 59, was taken to hospital in Riyadh on October 24 after he arrived to attend an economic forum.
Four days later, his spokesman, Ike Ngouoni, said the president had been admitted for "severe fatigue".
But last Sunday, Mr Ngouoni acknowledged that Bongo had been treated for a serious illness.
Following discomfort and "persistent vertigo... first tests revealed bleeding which justified medical surgical care in a highly specialised sector", he said, quoting a medical bulletin from doctors treating Bongo.
Mr Bongo's condition has now "greatly improved" and he is "recovering most of his functions," Mr Ngouoni added.
The National Union said the two statements were "completely contradictory" and warned it would be "grave and harmful" to the country if the government withheld vital information.
It called on Prime Minister Emmanuel Issoze Ngondet to fly to Riyadh "with a nationally representative delegation" to meet Bongo, the Saudi authorities and his doctors.
A foreign source close to President Bongo and his French-born wife Sylvia has told AFP that he had a stroke.
Gabon's official media watchdog on Friday said it had suspended the newspaper L'Aube (Dawn) for three months for an article saying the country had been put on a dangerous "autopilot" because of Mr Bongo's hospitalisation.
He took over from his father, Omar Bongo, who died in 2009 after nearly 42 years at the helm of the oil-rich West African state.
Gabon has large oil, mineral and tropical timber resources and its per capita national income is four times greater than that of most sub-Saharan nations.
But about a third of the population of 1.8 million still live below the poverty line -- the result, say experts, of inequality, poor governance and corruption.