The African Union has suspended Guinea-Bissau's membership after a coup last week by the West African state's military chiefs.
"The African Union (AU) Peace and Security Council decides to suspend with immediate effect Guinea-Bissau from all activities ... until restoration of constitutional order," Ramtane Lamamra said after a meeting in the bloc's headquarters in the Ethiopian capital on Tuesday.
The AU's suspension comes as leaders of the Economic Community of West African States (ECOWAS) said that military leaders in Guinea-Bissau agreed to hand back power and return the country to constitutional rule soon, after talks on Monday.
"After in-depth discussions, we agreed on the fact that the military accept the decision of ECOWAS to return to constitutional order," Desire Kadre Ouedraogo, president of the ECOWAS commission, told journalists after the meeting.
Ouedraogo said Ivory Coast President Alassane Ouattara, who chairs the regional bloc, would take steps with other parties, to return the country to constitutional rule in the coming days, but gave no specific timeline.
The second-place finisher in Guinea-Bissau's first round presidential vote held on March 18 denounced the military coup, when soldiers attacked his opponent's home with grenades and arrested him weeks before a runoff vote.
Kumba Yala, a former president who was himself overthrown in a 2003 coup, issued a statement along with four other ex-candidates, saying they all "strongly condemn all forms of taking power by force".
Prime Minister Carlos Gomes Jr, the favourite to win the runoff vote set for April 29, remains in military custody along with interim President Raimundo Pereira, who took power after Guinea-Bissau's president died in January.
A Portuguese government official, speaking on condition of anonymity because he was not authorised to speak to reporters, said Portugal had received information that both men were doing well.
The prime minister needed insulin and the Portuguese Embassy organised for the Red Cross to get it to him on Saturday, the official said.
Guinea-Bissau has weathered successive coups, attempted coups and a civil war since winning independence from Portugal in 1974.
The country has been further destabilised by a booming drug trade.
Cocaine is smuggled across the Atlantic Ocean from South America in boats and planes which dock on Guinea-Bissau's archipelago of Virgin Islands. The drugs are carried north to Europe.
The unrest in Guinea-Bissau takes place just weeks after mutinous soldiers overthrew the democratically elected president of Mali, who was about to retire after an April election.
The country's coup leader handed over power to an interim civilian president last week.
Guinea-Bissau's upheaval presents another dilemma for the regional ECOWAS bloc, which is already considering military force to topple rebels who declared independence in northern Mali.