ANTANANARIVO (Reuters) -Madagascar's presidency said on Sunday that an attempt to grab power by force was under way as more soldiers threw their support behind a youth-led protest movement that has rocked the African island nation for more than two weeks. Troops from the elite CAPSAT unit, which helped President Andry Rajoelina seize power in a 2009 coup, urged fellow soldiers to disobey orders on Saturday and back the demonstrators. The protests, initially over grassroots grievances, began on September 25 and now pose the most serious challenge to Rajoelina's rule since his reelection in 2023.