Madagascar's president Marc Ravalomanana has resigned, handing power to the military.

But the military has appointed opposition leader Andry Rajoelina as president of a transition government, after weeks of violent street protests by his followers.

Tanks and scores of soldiers guarded the Presidential Palace on Tuesday.

On Monday, Madagascar's traditionally neutral army threw its weight behind opposition leader Rajoelina, and stormed a presidential palace in the heart of the capital. But President Ravalomanana was not inside.

Weeks of opposition protests and turmoil on the Indian Ocean island have killed 135 people, crippled tourism and scared foreign investors in the mining and oil exploration sectors.

The 59-year-old president is holed up in another presidential palace on the outskirts of the capital, with supporters forming a human shield on roads outside.

The opposition leader has tapped into widespread public discontent with high levels of poverty.