ANTANANARIVO (Reuters) - Madagascar's army has given President Andry Rajoelina until the end of April to offer an acceptable way out of the 13-month political crisis on the Indian Ocean island, a military source said on Monday.

"The army bosses asked Rajoelina to present a road map in 48 hours, and after discussions everyone agreed on waiting until the end of the month," said a senior military source present at a meeting between Rajoelina and the military leadership.

A source close to the presidency confirmed the timetable. No details were given of what the army would do if Rajoelina failed to meet the deadline.

Political analysts say there has been growing unease in some quarters of the government and military at Rajoelina's handling of the crisis, which has unnerved major foreign investors exploiting the island's oil and mineral resources.

"We have asked the government, the High Transitional Authority, to publish a clear road map," army chief General Andre Ndriarijoana told reporters at an earlier news conference.

Ndriarijoana, who backed Rajoelina's ouster of former President Marc Ravalomanana in March last year, also demanded proof of how Rajoelina's administration would pay public sector salaries and finance legislative and presidential elections due later this year.

"We call on the politicians to end all street action and to take part in the building of a nation for all within a timeframe that we have given to the government," Ndriarijoana said.

Last month the African Union imposed targeted sanctions on Rajoelina and more than 100 of his key backers. The European Union is also mulling sanctions.

Rumours have swirled around Madagascar's capital in recent weeks of a planned coup to unseat Rajoelina.

The former disc jockey toppled former President Marc Ravalomanana with the help of renegade troops, among them Ndriarijoana, last March after weeks of violent street protests against Ravalomanana's increasingly authoritarian leadership.

A statement released by the presidency said it was paramount the armed forces were unified and underlined the need for the military "not to be manipulated for political means".

Late last week, Rajoelina's prime minister sacked Armed Forces Minister General Noel Rakotonandrasana in a show of no confidence. But Rakotonandrasana has refused to leave his post.

The army demanded Rajoelina offer a solution that would be acceptable to foreign donors who have suspended aid worth hundreds of millions of dollars.

"Above all, it is demanded the government work with all actors ... a necessary condition for a free and transparent election, accepted by the Malagasy people and the international community," said Ndriarijoana.