Tension is rising in Guinea, following the killing of senior army officer Col Mamady Condé.
It comes just two days before a presidential election in which President Alpha Condé is running for a controversial third term.
Residents of the nearby neighbourhood heard gunshots at 02:00 local time and heavy shooting continued for five hours.
There were reports of an attempted mutiny and that soldiers had seized weapons to free some of their colleagues who had been detained.
The minister of defence issued a statement saying that Col Condé had been killed.
The authorities said that the situation is now under control and that a search is under way to find the soldiers involved.
Mr Condé’s accession to power in December 2010 was the first genuinely democratic handover in his country’s 52-year independent history – a saga of authoritarian and military rule pockmarked with episodes of severe repression and spectacular brutality, the most recent of which had been the 28 September 2009 massacre, when troops killed at least 160 opposition supporters, and raped 110 women, attending a rally at the national stadium.
He had himself served jail time for challenging General Lansana Conté, who had ruled from 1984 to his death in 2008, and he faced a huge task to gradually reform the security forces and construct a democratically accountable state with a basic respect for human rights and transparent public finances.
The past 10 years have brought significant progress.
Early fears of a comeback coup by army hardliners gradually faded, and the military has been at least partly reformed, with many officers sent into retirement.
A team of capable technocratic ministers has got the economy back on track, rebuilding a solid cooperative partnership with the International Monetary Fund (IMF) and the donor community.
Guinea has huge mineral wealth and regulation of the extractives sector has been overhauled.