Madagascar's government has called for dialogue with the group of military officers who said on Wednesday they had taken over the island nation.
The mutineers are holed up next to an army barracks near the airport of the capital Antananarivo.
Some of the officers were behind the coup that brought President Andry Rajoelina to power last year.
Their power bid came on the day of a referendum on a new constitution that could legitimise Mr Rajoelina's rule.
He has been diplomatically isolated since coming to power in March 2009 and has ignored attempts by regional mediators to broker a consensus with the opposition.
Madagascar has been beset by instability for several years.
The officers said they had dissolved government institutions and formed a military committee.
They are threatening to close Malagasy airspace and if necessary march on the presidential palace.
However, correspondents say so far there has been little of sign of other sections of the army joining them.
Journalist Hannah McNeish in Antananarivo told the BBC's Network Africa that Mr Rajoelina is keen to seek dialogue.
The coup plotters are made up of an elite of the army, among them Col Charles Andrianasoavina who was instrumental in bringing Mr Rajoelina to power.
The government also wants to avoid bloodshed while the nation awaits the results of the referendum, Ms McNeish says.
On national television Prime Minister Camille Vital called on soldiers to "respect discipline, respect institutions and show professionalism", AP news agency reports.
The new constitution would allow Mr Rajoelina to stay in power as long as it takes to organise an election.
It would also lower the age limit for presidential candidates from 40 to 35 years, allowing the 36-year-old to stand.
Mr Rajoelina, who has said he will not run for president, organised huge rallies in support of a yes vote.
He is a former DJ and mayor of the capital city and rose to power on wave of popular support.
But some analysts say his failure to end leadership squabbles has eroded some of his popularity.
In the run-up to the referendum there were many demonstrations against it - and all three of the main opposition groups, each led by an ex-president, called for a boycott.