Deputy Prime Minister Wong Kan Seng, who is also Home Affairs Minister, gave this warning on Wednesday when he explained the need for a strong approach during the November meetings.

'As many important heads of state and government will be here for the Apec Summit, we have to anticipate that it may attract terrorist interest. This is why we have to be very firm with protesters and anarchists who may engage in acts of violence, or deliberately cause law and order problems,' he said.

'We cannot afford to be distracted from our graver mission of ensuring the security of the event, the delegates and Singaporeans against terrorists.'

United States President Barack Obama and China's President Hu Jintao are among the leaders expected at the summit.

Mr Wong's speech, at a promotion ceremony for Internal Security Department (ISD) staff, came two days after Parliament passed the Public Order Act, which gives the police more effective powers in dealing with public order problems.

Mr Wong's remarks put on notice foreigners who may plan to cause a scene here during Apec, or who plan to instigate Singaporeans to break the law through acts such as staging street protests.

'In Singapore, it is only a tiny group of irresponsible and selfish individuals who have been pushing this line of civil disobedience,' said Mr Wong, noting that there are existing avenues for them to express their views within the law.

Another challenge facing the ISD this year is preserving social cohesion during an economically tough time 'when the population is under stress', he said.

'ISD has a critical responsibility in helping to ensure individuals and incidents don't threaten our racial and religious harmony.'

Read the full story in Thursday's edition of The Straits Times.