Ouagadougou (AFP) - The African Union suspended Burkina Faso and slapped sanctions on the leaders of its military coup Friday as troops fired in the air to stop protesters from marching on the capital's Revolution Square.
"All measures taken by those who took power by force in Burkina Faso are null and void," Kenya's AU ambassador AU Mull Katende added.
The strong AU reaction came as Senegalese President Macky Sall, chairman of the Economic Community of West African States (ECOWAS), and Benin President Thomas Boni Yayi arrived in Ouagadougou in a bid to end the crisis.
They immediately met with coup leader General Gilbert Diendere -- Compaore's former chief of staff -- for talks.
As they arrived, members of the elite presidential unit that spearheaded the coup fired in the air to disperse protestors who were trying to march on Revolution Square, the epicentre of a popular uprising that overthrew Compaore in October 2014.
He was forced to flee the country after trying to extend his 27-year rule over the impoverished west African nation.
Compaore's Presidential Security Regiment (RSP) formally seized power on Thursday after complaining that the transitional government, led by interim president Michel Kafando, was excluding the ex-president's supporters from the upcoming October 11 polls.
But coup leaders released Kafando and two ministers Friday -- saying this was "a sign of easing tensions" -- but prime minister Isaac Zida, a former officer in the RSP, remained under house arrest.
- 'Brutal and murderous' -
Anti-coup protests have spread to several cities and towns. In the country's economic capital Bobo-Dioulasso, women gathered on Friday holding spatulas and brooms -- symbols of the Balai Citoyen ("Civic Broom") movement at the forefront of last year's anti-Compaore protests -- showing they wanted to clean up the country's politics.
Burkina Faso had been preparing to hold its first democratic election in decades before the coup threw the nascent democracy into turmoil.
The international community has unanimously condemned the coup, with the UN, AU, European Union, ECOWAS, the United States, and former colonial power France denouncing the junta.
Parties opposed to Compaore on Friday demanded the restoration of the transitional authorities and urged that elections be held in October as planned.
The parties, led by former presidential favourite Roch Marc Christian Kabore, called for a campaign of civil disobedience and an immediate end to the coup leaders' "brutal and murderous oppression".
- Where is Compaore? -
In Ouagadougou there were fewer cars on the road on Friday than usual, with some shops locked shut. Clashes between coup forces and protesters on Wednesday and Thursday left at least three people dead and 60 wounded, according to a hospital source.
The military had earlier announced a curfew and closed land and air borders, reopening them on Friday afternoon.
Coup chief Diendere has denied that the coup was orchestrated by the former president Compaore, whose whereabouts are unknown.
But analysts have cast doubt on suggestions that Compaore could have been completely unaware of plans for a takeover by his old aide.
"It's a question we cannot answer -- because by definition, Blaise Compaore never speaks," said Rinaldo Depagne, an analyst with the International Crisis Group based in Dakar.
"But it is difficult to imagine that Blaise Compaore would be unaware of a project that was so meticulously prepared."
Diendere has insisted that he is committed to holding elections, saying on Thursday evening: "We do not intend to drag this on, we do not intend to stay."
The presidential and legislative elections slated for October were supposed to mark the end of the transitional government installed after Compaore was toppled.
"Handsome Blaise" had ruled the country since assuming power in a 1987 coup, which ended in the mysterious death of President Thomas Sankara, seen by many still in west Africa as a revolutionary hero.