"The (AU's) Peace and Security Council decides to suspend with immediate effect Guinea Bissau from all activities...until restoration of constitutional order," AU Commissioner for Peace and Security Ramtane Lamamra said in Addis Ababa.
Foreign governments and international organizations have condemned Guinea-Bissau's military for cutting short a presidential election in the impoverished West African state, detaining front-runner and former Prime Minister Carlos Gomes as well as interim President Raimundo Pereira, Reuters reports.
Guinea-Bissau's Catholic bishops also condemned the coup, while Amnesty International accused the army of clamping down on protests, the media and freedom of movement.
The former Portuguese colony has seen several coups and army revolts since independence in 1974 and the latest is a blow to Western donors' efforts to reduce military meddling in politics and counter the influence of Latin American drug-trafficking cartels using the country as a transshipment point.
Suspension is the African Union's normal response to any interruption of constitutional rule in one of its members.
A high-level delegation from the West African regional grouping ECOWAS met Guinea-Bissau's military overnight and ECOWAS Commission head Desire Kadre Ouedraogo told reporters there was an agreement "on the return to constitutional order".
Lieutenant-Colonel Daha Bana na Walna, spokesman for the Guinea-Bissau army leadership, said ECOWAS would send a technical team to help restore civilian rule. He said the country was calm and there was no disorder.
ECOWAS had also insisted in the talks that Gomes Junior and Pereira be released. "As soon as the conditions of security exist for this, they will be freed," na Walna said.
But he later told reporters in Bissau that the return to political power of Gomes Junior and Pereira was "out of the question", and confirmed that the aim of the April 12 army intervention had been to end their mandates.
Many residents have fled the tense uncertainty of post-coup life in Bissau, the crumbling coastal capital, for the interior.
The military chiefs, appealing for calm, said in a communique they were banning all public demonstrations.
Amnesty said fear and insecurity were growing after the military halted protests and shut down private radios.
"Increasingly repressive measures are being employed by the military as they try to stifle mounting criticism within the country and internationally," Marise Castro, Amnesty International's Guinea Bissau expert, said in a statement.
SHADOWY COUP LEADERSHIP
The London-based rights group called for the release of Gomes Junior and Pereira, saying they were being held at Mansoa Barracks, 60 km (37 miles) northeast of Bissau. "Reportedly, both men are being held incommunicado in a mosquito-infested small cell with no water or toilet facilities," it said.
Gomes Junior suffers from diabetes, Amnesty added.
Na Walna told reporters the two men were being well treated and were receiving food prepared by their own families.
It was the second coup in West Africa in less than a month. A March 22 military takeover in Mali left that Sahel country split in two with Tuareg and Islamist rebels holding the north.
Guinea-Bissau's military has announced the formation of a "national transition council" to prepare for fresh elections. But the main political party, PAIGC, has refused to take part, robbing this move of any credibility.
Gomes Junior and Pereira are PAIGC members, and the former was expected to win a presidential election run-off on April 29, which was prevented by the coup.
Gomes Junior was unpopular with military chiefs because he backed plans to reform the bloated army, which is accused of involvement in drug-trafficking by Western security agencies.
Confusion persists over who masterminded the coup.
A shadowy self-styled "Military Command" said it acted to head off what it alleged was a secret pact between Gomes Junior and Angola to "annihilate Guinea-Bissau's armed forces".
Angola had been providing military trainers and advisers to the smaller state in a military cooperation mission. But it announced earlier this month that it was ending the mission.
Guinea-Bissau military spokesmen have declined to confirm rumors that armed forces Chief of Staff General Antonio Indjai was also removed in the coup, saying only that he was "safe".
Many believe Indjai, the nation's most influential military figure, was the architect. "The question has been whether Indjai is in detention or behind the coup but the consensus now is that it is the latter," one Bissau-based diplomat said.
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