More than three million Roman Catholic worshippers paraded with a charred Christ statue through the Philippine capital in an annual procession Monday despite a warning from the president that terrorists might target the gathering.

The black wooden statue known as the Black Nazarene was displayed at the seaside Rizal Park where Manila's Archbishop Luis Antonio Tagle led a Mass and offered prayers for victims of tropical storms and landslides over the past year.

Organizers then brought the statue — believed to have healing powers — down from the stage for its five-kilometre procession to a popular church as devotees rushed forward to touch it. Police estimated that more than three million people had joined the procession; up to nine million were expected.

President Benigno Aquino III warned Sunday at a hastily called news conference, along with military and police officials, that several terrorists planned to disrupt the event and had reportedly been seen in the capital. But the threat was not high enough to cancel the procession and police were working hard to thwart any attack, he said.

"The sad reality of the world today is that terrorists want to disrupt the ability of people to live their lives in the ways they want to, including the freedom to worship," Aquino said in the nationally televised conference.

6 to 9 believed to be behind plot

The government banned cellphones and firecrackers at the event. Around 15,000 policemen were deployed with sniffer dogs, while ambulances and hospitals were on standby, according to an entry in Aquino's Facebook page.

Australia urged its citizens to avoid the procession and nearby areas.

Interior Secretary Jesse Robredo said without elaborating that six to nine people from the southern Philippines may be involved in the plot, and officials gave no description of their group or its motives. When asked if the threat came from the al-Qaeda-linked Abu Sayyaf group, Aquino said that possibility had not been confirmed.

Defence Secretary Voltaire Gazmin told reporters that raids had been conducted in several suspected terrorist safe houses Manila and nearby Rizal province but without any results so far.

The wooden statue of Christ, crowned with thorns and bearing a cross, is believed to have been brought from Mexico to Manila in 1606 by Spanish missionaries. The ship that carried it caught fire, but the charred statue survived and was named the Black Nazarene.

Some believe the statue's survival of fires and earthquakes through the centuries and intense bombings during World War II is a testament to its powers.

The Philippines is Asia's largest predominantly Roman Catholic nation.