A Madagascan court sentenced former president Marc Ravalomanana in absentia on Saturday to life in prison with hard labour for the deaths of dozens of protesters during a march on the presidential palace last year.

The verdict could open a fresh challenge to an African Union-backed effort to end the Indian Ocean island's political crisis that followed Mr Ravalomanana's removal by President Andry Rajoelina.

Those killed were supporters of Mr Rajoelina who had called a march on the presidential palace on 7 February 7 2009. During the rally, security forces opened fire, killing at least 30 people.

Mr Ravalomanana, who lives in exile in South Africa, was not present at the trial. The deposed leader was charged with murder and being an accessory to murder, along with 18 other people, some of whom are also in exile.

The country has been in the midst of a political crisis for the past 19 months. The crisis has stunted economic growth on an island known for its deposits of oil, coal, uranium, chrome, nickel and cobalt.