Guinea is among several countries to have seen coups since 2020, along with Mali, Burkina Faso and this year, Niger and Gabon.
A heavy gunfire erupted on Saturday in the centre of the Guinean capital Conakry as security forces blocked off the area.
An eyewitness from the area speaking on condition of anonymity told AFP that the city has been sealed down.
"There is gunfire from both automatic and weapons of war in Kaloum," the political and administrative heart of the seaside city, a witness from the area said, speaking on condition of anonymity.
"The city centre has been sealed since dawn, we can neither enter, nor leave," a shopkeeper added, also speaking on condition of anonymity.
"I wanted to go to the port area where I work but was prevented from leaving (Kaloum), where armoured vehicles have been deployed".
Guinea is among several countries to have seen coups since 2020, along with Mali, Burkina Faso and this year, Niger and Gabon.
The head of Guinea's junta Colonel Mamady Doumbouya came to power in a coup in September 2021 after 11 years of civilian rule.