“ECOWAS condemns the coup attempt and holds the military responsible for the physical integrity of President Umaro Sissoco Embalo and members of his government,” ECOWAS said in a statement.
“ECOWAS asks the military to return to their barracks and maintain a republican posture,” the statement concluded.
Mamadou Jao, an academic in Guinea Bissau, told CNN that the streets were quiet across the capital, as worried residents stayed inside awaiting more information.
Jao added that the power was off in homes saying: “The place is in darkness for about three or four hours. It is not something that happens normally.”
The UN Secretary-General Antonio Guterres also called for an immediate end to the fighting.
Guinea-Bissau’s history has been marked by several military coups since the country gained independence from Portugal in 1974.
These conflicts have ravaged the country’s infrastructure and economy, leaving it among the poorest in the world.