Police in the Philippines' capital estimate at least 3 million Catholics have joined an annual religious procession, despite a warning from the president that Islamic militants might target the gathering.

The huge crowed of worshippers gathered Monday around a life-sized wooden statue of Jesus, known as the Black Nazarene, which believers say has healing powers.

President Benigno Aquino warned Sunday that authorities had discovered a plot by militants to disrupt the parade in Manila. He said police were attempting to detain the suspects.

Mobile phone service along the procession route has been blocked to thwart remote-triggered bombs. Officials say 15,000 police have been deployed for the parade's security. Police estimate at least 9 million people will join the procession before it ends.

The wooden statue of Jesus is believed to have been brought to Manila from Mexico in 1606.

At least 80 percent of of the Philippines' population is Catholic, a legacy of the country's Spanish colonial past.