Andry Rajoelina (L) has the support of the military
Madagascar's leader Andry Rajoelina has formally abandoned a power-sharing peace deal a day after appointing a military prime minister.
Col Vital Albert Camille was named to replace consensus Prime Minister Eugene Mangalaza, who was sacked by Mr Rajoelina on Friday.
Mr Rajoelina said he was also scrapping the two posts of co-president set up under the power-sharing deal.
Mr Rajoelina, a former DJ, came to power with military backing in March.
The power-sharing deal was agreed after longs talks with the opposition, including supporters of ousted President Marc Ravalomanana.
Madagascar has been riven by political turmoil for almost a year, with Mr Rajoelina taking power after weeks of protests which saw dozens of people lose their lives.
In the statement announcing that he was scrapping the power-sharing deal, Mr Rajoelina warned this meant that any opposition attempt to convene parliament would be illegal.
The BBC's Christina Corbett in Madagascar says the announcement seems to be a complete reversal of any progress made so far to solve Madagascar's political crisis.
A YEAR OF TURMOIL
Dozens killed in protests sparked after President Ravalomanana shuts opposition media houses
Opposition figurehead Andry Rajoelina sacked as mayor of Antananarivo
Army mutiny, Mr Ravalomanana resigns and flees country, Mr Rajoelina takes over, African Union suspends Madagascar
Power-sharing deal signed, later breached by Mr Rajoelina
New power-sharing deal, breached by Mr Rajoelina in December
She says this breakdown will be hugely disappointing for the African Union, the Southern Africa Development Community and the UN, as all three organisations have invested much time and money facilitating talks between the rival leaders - sending some of their top envoys to help with negotiations.
Our reporter adds that the military will be closely watched, as with the appointment of a colonel as prime minister, the armed forces appear to be increasingly politicised.
After chairing his first cabinet meeting on Sunday, Col Vital said: "We are in a very difficult, even frightening situation."
In an address broadcast across the nation, he also called on the opposition to work with the government.
He said his priorities were to deliver security and organise elections.
One senior opposition figure has said Col Vital's appointment is illegal, according to Reuters news agency.
Mr Mangalaza was sacked just a day after Mr Rajoelina called a parliamentary election for 20 March 2010.
He initially said he would appoint Cecile Manorohanta as prime minister, before naming Col Vital on Sunday.
Donors have frozen aid and say funding will not be resumed until a power-sharing government takes office and new elections held, Reuters reported.