Antananarivo - The mayor of Madagascar's capital said on Monday he had approached the country's Supreme Court with a list of complaints against President Marc Ravalomanana and a request to strip him of his powers.
Andry Rajoelina, 34, who has led a wave of anti-government protests over the past 10 days, also said he would start putting together a transitional government, which he says he will lead.
Ravalomanana, 59, who was reelected to a second five-year term in 2006, has dismissed the mayor's coup threat and declared he is fully in control of the impoverished Indian Ocean island.
Around 25 000 people attended the mayor's rally on Monday in central Antananarivo, where opposition leaders called for daily demonstrations until Rajoelina is installed as interim president.
The dwindling attendance at the protests, however, and the resumption of business as normal in Antananarivo on Monday suggested flagging support for the mayor in his bid to unseat Ravalomanana.
More than 100 people died in three days of upheaval on the island last week when an opposition demonstration protesting what Rajoelina's calls the president's growing authoritarianism degenerated into widespread looting and destruction of property.
UN secretary General Ban Ki-moon told an African Union summit in Ethiopia Monday he was very "particularly concerned" about the developments and urged the parties to address their differences peacefully. - Sapa-DPA