Madagascar's army said it will take control of the country's affairs if feuding leaders do not resolve a political crisis within 72 hours.
Army Chief of Staff General Edmond Rasolomahandry issued the ultimatum speaking to reporters Tuesday.
He said the military would not take sides but is prepared to act in order to protect national interests.
Madagascar has endured weeks of rising tension, amid anti-government protests and calls by the opposition for President Marc Ravalomanana to resign.
More than 100 people have died in the protests, many at the hands of government security forces.
The president went on national television Tuesday, admitting to making mistakes and calling for national unity. He said a national conference would begin Thursday to find a solution to the crisis.
Also on Tuesday, Madagascar's defense minister, Mamy Ranaivoniarivo, resigned after just a month on the job. Reports indicated he stepped down under pressure from the army.
The resignation came two days after a group of soldiers mutinied, saying they will not accept orders to fire on anti-government protesters.
The defense minister's predecessor also resigned in February, after the presidential guard shot and killed 28 demonstrators in the capital.
The U.S. State Department has issued a travel warning for Madagascar and has authorized non-emergency personnel and family members at the U.S. embassy there to leave.
Meanwhile, the United Nations continues to guard Madagascar's opposition leader Andry Rajoelina. Reports Tuesday said he is inside the French Embassy.
The opposition leader has been leading the protests against the president, who he accuses of becoming authoritarian.
The United Nations, the African Union and local mediators have been trying to mediate the crisis between the two men, so far without success.
Some information for this report was provided by AFP and Reuters.