Jakarta  - Indonesia on Monday marked its Independence Day amid tight security a week after police said they had foiled a plot to assassinate President Susilo Bambang Yudhoyono using a bomb-laden car driven by a suicide attacker.

Yudhoyono led a moment of silence for the people who died in the struggle for independence from Dutch colonial rule in a ceremony at the state palace in Jakarta.

Yudhoyono made no speech at the solemn ceremony as tens of millions of people across the world's fourth most populous nation celebrated Independence Day with joyful activities, such as fireworks, neighbourhood contests, parades and dance performances.

Among the most popular games to mark the celebrations is "Panjat Pinang," in which individuals and groups struggle to reach the top of a greased betel nut palm trunk, vying for prizes ranging from new motorcycles to towels and plastic buckets.

In Indonesia's easternmost province, Papua, Independence Day celebrations were marred by the hoisting of a flag belonging to the Free Papua Movement, a separatist group fighting for an independent Papua, the state-run Antara news agency reported.

In Jakarta, security was tight around the presidential palace as thousands of police and soldiers were deployed to safeguard the ceremony there attended by hundreds of guests, including foreign dignitaries and diplomats. Security personnel also closed down several roads around the palace.

After a four-year lull in terrorist attacks, the world's most populous Muslim nation was jolted July 17 by bombings at Jakarta's JW Marriott and Ritz-Carlton hotels, which killed nine people, including two suicide bombers, and injured 53.

In a state-of-the-nation address Friday, Yudhoyono, who was re-elected to a second, five-year term July 8, pledged to defeat terrorism and urged Indonesians to support the government's effort to fight terrorism.

"I would like to reaffirm that the nation must not and will not be defeated by terrorism," Yudhoyono said. "The government that I am leading will run its course to protect serve and improve the welfare of the whole nation."

Police said they had foiled a plot to blow up Yudhoyono's private residence using a suicide truck bomb when officers on August 8 raided a house rented by suspected militants involved in last month's hotel bombings.

Police had intensified the hunt for terrorist suspect Noordin Mohammed Top, one of Asia's most wanted terrorist suspects, accused of masterminding the July 17 bombings.

The Malaysian-born militant managed, however, to elude police in a dramatic raid on a house in Central Java, also on August 8. Contrary to earlier media reports that Noordin has been killed in the raid, DNA test confirmed last week that the man slain in 18 hours of gunfire at the house was a hotel florist named Ibrahim whom police claimed helped plan the hotel bombings.

Noordin, believed to be the leader of a splinter group of the radical Islamist terrorist network Jemaah Islamiah, is also accused of masterminding the 2003 suicide bombing on the same Marriott hotel in Jakarta, which killed 12 people, and the 2004 attack on the Australian embassy in the Indonesian capital, in which 11 people were killed. (dpa)