No country is immune to the threat of terrorism and it is no secret that Asean cities - Kuala Lumpur, Jakarta, Singapore and Manila - are targets for terror plots, said Defence Minister Ng Eng Hen.

"It has already been declared by leaders of extremist movements that they want their followers to target us. It is, if you like, a general command: Go and attack them," he said.

"No country is immune. If you look at the number of attacks that have occurred across all cities, not only have the attacks within each city gone up, but the number of cities that have been attacked has also gone up, " he added.

Dr Ng, an MP for Bishan-Toa Payoh GRC, was speaking to reporters yesterday at a community sports day organised by the People's Association.

Some 40,000 residents took part in activities with a racial and social harmony theme at 76 community clubs. At Toa Payoh Central Community Club, for example, more than 60 participated in a race where they had to go through five stations and clear 40 tasks such as quizzes on race and culture.

Dr Ng said this community sports day - now in its second year - signals unity.

"Sports is quite an antidote to the different forces that are pulling communities apart now - including religion, sometimes language - particularly because of the threat of terrorism, when people misuse religion to tear communities apart," he said.

Dr Ng said recent attacks have been carried out by lone wolves radicalised via the Internet, which makes its harder for security agencies to track them.

He said: "If you suspect someone is being radicalised, you can help him. You can help him because if you alert the agencies early, there are deradicalisation programmes.

"What these programmes have shown is that people have realised - after talking to religious leaders, community leaders and their families - that, 'Oh, I was misled', and suddenly they wake up... and they change their course and they go back into the community and they continue to be productive citizens."