The African Union has suspended Mali's membership after soldiers on Tuesday ousted the nation's president and his government.
The Pan-African body's Peace and Security Council said Wednesday the suspension would remain in effect until the restoration of constitutional order in the West African nation.
It also demanded that President Boubacar Keita and other senior officials be released.
In a related development, local heavyweight Nigeria condemned the coup in Mali, demanding an immediate "restoration of constitutional order".
"The Nigerian Government unequivocally condemns the coup d'état that took place in Mali yesterday and demands the immediate and unconditional restoration of constitutional order," Nigeria's Foreign Minister tweeted Wednesday.
"We welcome the urgent activation of the ECOWAS Standby force," it added, referring to the Economic Community of West African States, an influential 15-member political and economic bloc.
Keita announced his resignation Tuesday after being detained by soldiers. Prime Minister Boubou Cisse was also detained.
Tensions erupted in Mali in 2012 following a failed coup and a rebellion by Tuareg separatists that ultimately allowed al-Qaeda-linked militant groups to take control of the northern half of the country.
Keita, 75, came to power in 2013 but has been criticized by some who say he has failed to protect them from terrorist attacks mostly in the northern and central part of the country.
Mali, one of the poorest countries in the world, suffers from the presence of several terror groups, despite the presence of French, Malian, and UN peacekeepers who carry out counter-terrorism operations.
A 2015 peace agreement between the government and Tuareg rebel groups could not be implemented.
