Reports from Madagascar's capital, Antananarivo, say police have fired on anti-government protesters, killing at least 25.
State-run and independent media reports say police fired into the crowd earlier Saturday as demonstrators marched toward the presidential palace.
Opposition leader and former Mayor of the capital Andry Rajoelina had said he would form a transitional government Saturday if President Marc Ravalomanana refused to resign.
On Tuesday, government officials fired Mayor Rajoelina. But he rejected the move and appealed to both the Constitutional Court and parliament to remove the president from office.
The political opposition has held a series of rallies and protests against the government over the last two weeks. An estimated 100 people died when the protests turned violent last week.
Late Friday, The United Nations announced it is sending a special envoy to Madagascar in a bid to avert further violence in the country.
U.N. Assistant Secretary-General for Political Affairs Haile Menkerios is scheduled to visit Madagascar for four days beginning Saturday.
The world body says the government of Madagascar invited Menkerios, who will meet with government officials and other concerned parties.
Some information for this report was provided by AFP, AP and Reuters.