MANILA -- President Gloria Macapagal Arroyo declared a state of emergency today as she struggled against a reported coup plot and a possible repeat of the protests that ousted two of her predecessors.
The announcement was made after the military said a general had been arrested in connection with a coup plot and as people defied a ban on rallying at a shrine of the 1986 revolt that ousted dictator Ferdinand Marcos. Clashes erupted as police tried to disperse the protesters.
Arroyo said her action was the result of ongoing efforts by the political opposition, along with both the extreme left and the extreme right, to bring down the elected government.
''I am declaring a state of emergency because of the clear threat to the nation," a defiant Arroyo said in a taped, nationally televised statement.
''This is my warning against those who threaten the government: The whole weight of the law will fall on your treason. You are unhinging the economy from its strengthening pillars."
Arroyo contended that the military had quashed an effort by some military officers and their men to intervene in politics.
''There were a few who tried to break from the armed forces' chain of command, to fight the civilian government and establish a regime outside the constitution," Arroyo said. ''We crushed this attempt."
Military chiefs said they backed the democratically elected Arroyo. They arrested an army general who leads an elite special forces unit, accusing him of taking part in a coup plot.
''We have reduced the threat," said the army chief of staff, General Generoso Senga. ''We cannot say that it has been stopped."
An unspecified number of other people also were taken into custody, and police were seeking eight to 10 more, said Arroyo's chief of staff, Mike Defensor.
Already-tight security was bolstered in the capital. The government canceled rally permits and told schools to call off classes, aiming to keep the opposition from exploiting scheduled demonstrations commemorating the 20th anniversary of the peaceful revolt that ousted Marcos.
Extra barbed wire and shipping containers were set up on roads leading to Malacanang, the presidential palace, and only essential staff members were allowed to enter. Checkpoints were set up around the capital.
Army Chief Lieutenant General Hermogenes Esperon said that 14 junior officers were involved, and thatseized documents outlined the plot. He said it included establishing a revolutionary government after Arroyo was forcibly removed and abolishing ''democratic institutions."