The fate of Guinea's President Alpha Condé is unclear after an unverified video showed him in the hands of soldiers, who said they had staged a coup.
However, the defence minister has been quoted as saying the attempted takeover had been thwarted.
This follows hours of heavy gunfire near the presidential palace in the capital, Conakry.
Soldiers are patrolling the otherwise deserted streets of the city centre.
Terrified residents of the central Kaloum district have heeded their orders to stay at home.
In the video, the soldiers from a unit of elite special forces ask President Condé to confirm he is unharmed but he refuses to respond.
They say that all land and air borders have been closed and the government dissolved.
The only bridge connecting the mainland to the Kaloum peninsular, which houses most ministries and the presidential palace, has been sealed off and many soldiers, some heavily armed, have been posted around the palace, a military source told Reuters news agency.
There are unconfirmed reports that three soldiers have been killed.
President Condé was re-elected for a controversial third term in office amid violent protests last year.
Cullied from BBC