Police and elite soldiers fired volleys of shots into the air late last night as they drove back thousands of supporters of deposed Philippine leader Mr Joseph Estrada from the gates of the presidential palace.
A military aide told Reuters that President Gloria Arroyo was meeting cabinet ministers inside the palace. Presidential Chief-of-Staff Renato Corona told local radio that one policeman had been killed and many wounded in the violence.
Several protesters tried to scale the gates of the Malacanang Palace but were driven back. Police and soldiers from the presidential guard eventually drove the stone throwing marchers some 200 yards from the gates.
"They fired repeatedly into the air and the crowd pulled back," said Reuters journalist Michael Barker.
Newspapers have said opposition politicians and military officials were planning a coup to install a civilian-military junta which would later call a snap presidential election.
Police estimated the protesters at between 10,000 and 20,000 as they marched to the palace from a religious shrine in central Manila. The march began from a shrine about nine miles from the palace where Mr Estrada's supporters have been holding a protest vigil since the former president was detained six days ago on a charge of plundering the economy.
Mr Estrada was last night flown by helicopter to a maximum security detention centre at Laguna City, 30 miles south of Manila, according to local radio.