Two tanks forced their way into a presidential palace in Madagascar's capital and two explosions rocked the city today soon after the armed forces publicly backed opposition leader Andry Rajoelina in his power struggle with President Marc Ravalomanana.
A few bursts of gunfire rang out in Antananarivo and soldiers were positioned around the palace, Reuters witnesses said.
Ravalomanana was not in the building. He has been sheltering in another palace about 10 kms (6 miles) from the city centre.
Rajoelina had called today for the security forces to arrest Ravalomanana, who has resisted growing pressure to resign over the crisis in the Indian Ocean island in which at least 135 people have been killed.
The president says he will only step down democratically and has offered a referendum on whether he should stay.
The army has traditionally remained neutral during periods of political volatility since independence from France in 1960.
But on Monday Colonel Andre Ndriarijaona said: "If Andry Rajoelina can resolve the problem, we are behind him."
"I would say 99 percent of the forces are behind him," he told a news conference in the capital Antananarivo, also attended by Madagascar's military police and national police.
Christine Razanamahasoa, appointed minister of justice in Rajoelina's parallel administration, earlier said she was ordering prosecutors to arrest the president.
The African Union condemned what it called an attempted coup by the opposition and urged the people of Madagascar to respect the constitution.
"The situation in Madagascar is an internal conflict. It is an attempted coup d'etat. We condemn the attempted coup d'etat," Edouard Alo-Glele, Benin's envoy to Ethiopia, said after an emergency meeting of the AU's Peace and Security Council.
Rajoelina, 34, a former disc jockey who was sacked as Antananarivo's mayor last month, says Ravalomanana is an autocrat running the island like a private company.
The president's supporters call Rajoelina a troublemaker bent on seizing power illegally.
While Rajoelina has tapped into widespread public discontent, especially with high levels of poverty, many inhabitants are fed up with the unrest.
The $390 million-a-year tourism sector is nosediving, and foreign investors in the important mining and oil exploration sectors are watching events nervously.
The United Nations has sent Tiebile Drame, Mali's former foreign minister, to mediate.