There was a heavy military presence on the streets of Madagascar on Monday night after the opposition leader refused to accept the president’s offer of a referendum to end a stand-off that appears to be nearing boiling point.

Reports suggested tanks under the command of renegade officers loyal to opposition leader Andry Rajoelina had stormed the presidential palace. Marc Ravolmanana, the president, is holed up at his residence in a different part of Antananarivo, the Indian Ocean island’s capital.