Thousands of protesters massed in the Philippine capital on Friday with some hurling tomatoes at images of President Gloria Arroyo and her husband, demanding their ouster for alleged corruption.
Authorities enforced high security, with at least two light tanks, six armoured cars and numerous troops arriving to reinforce soldiers already based in Manila ahead of the event, military officials said.
More than 3,000 marchers including 79-year-old former vice-president Teofisto Guingona, lawyers, nuns, priests and students marched in the city's financial district of Makati.
Some carried placards saying "guilty, guilty" while a banner displayed a caricature of Arroyo lying on bags of cash.
An image of Arroyo and her husband with the slogan "couple in crime" emblazoned on it, was pelted with tomatoes while protesters chanted "enough is enough. Overthrow Gloria."
Another Arroyo-adorned poster proclaimed: "Moderate Your Greed."
Some workers in buildings overlooking the rally showered the protesters with confetti in a show of support. The crowd had thinned out to a few hundred by early evening, according to police.
Observers said the protest was noticeably smaller than previous rallies held in Makati, a stronghold of the anti-Arroyo opposition forces.
Many offices in Makati allowed their employees to go home early to avoid getting caught in traffic jams caused by the protest.
Makati Mayor Jejomar Binay, a leader of the opposition, charged that government forces were preventing protesters from other areas joining the rally.
The demonstration was called to demand Arroyo's ouster over fresh claims that her husband and a political ally tried to gain millions of dollars in kickbacks from a telecoms deal with a Chinese firm.
The president cancelled the $329 million national broadband network deal with China's state-run ZTE as a result of the graft allegations.
In an address to businessmen in Makati earlier in the day, Arroyo said she ordered a "thorough and transparent" probe into the corruption claims.
"We do not want to tolerate corruption. There is no room in the development of our country for wasting money on corruption when so much remains to be done to invest in the nation," she said.
Troops and armoured vehicles had rushed to the Philippine capital on Friday to beef up security ahead of the protest against Arroyo.
The military had warned that communist insurgents could infiltrate and disrupt the rally, but opposition spokesmen have dismissed the claim as a ploy to justify tightened security.
Security officials revealed on Thursday that they recently uncovered a plot by suspected Al Qaeda-linked Islamic militants to assassinate Arroyo, but this was unrelated to Friday's rally which no major political figures attended.
Renegade soldiers detained for mounting failed mutinies to topple Arroyo, declared their support for the rally, saying "now is the time to choose a new leader for the country."
Jose Maria Sison, chairman of the insurgent Communist Party of the Philippines urged the military and police to "withdraw support from the Arroyo ruling clique." (AFP)
Philippine protesters march against President Arroyo