A new battle has emerged on cyberspace and social media platforms.
The weapons: messages by terrorist groups seeking to incite hate and discrimination.
To fight back, one needs a rational mindset that can reject such messages. It is a form of social resilience that is increasingly important, said Senior Minister of State for Defence Maliki Osman yesterday.
Speaking on Total Defence Day at at The Future of Us, an exhibition at Gardens by the Bay, Dr Maliki said: "The real battle of today and of the future is for the hearts and minds of our people."
Groups such as the Islamic State in Iraq and Syria (ISIS) have used the Internet and social media to recruit followers and successfully spread their ideology, said Dr Maliki, who is also Senior Minister of State for Foreign Affairs.
He named terrorism as the biggest threat facing all countries, and warned terrorist attacks that have struck Paris, Istanbul and Jakarta remain a possibility in Singapore.
Nearly 1,000 men and women from South-east Asia, including Singapore, have travelled to the Middle East to fight for ISIS and they pose a serious threat to Singapore's security, he said.
Singapore's Total Defence strategy relies on the five pillars of military, civil, economic, social and psychological defence, and yesterday Dr Maliki paid special attention to the last two as the only way to reject extremist ideologies and to come back from any acts of terror.
Agreeing, Dr Shashi Jayakumar, head of the Centre of Excellence for National Security, cited US Director of National Intelligence James Clapper, who lists cyberthreats as the most potent emerging threat, followed by terrorism.
Dr Shashi termed cyberthreats as "slow burn" threats that erode resilience and thus ultimately a nation's defence capabilities.
Social defence forms an important aspect of prevention in which Singaporeans will alert the authorities to people they know who are being radicalised.
Also yesterday, a discussion was held on Total Defence and the changing face of threats. Some 80 participants, including 47 ordinary Singaporeans, shared their views on what these were.
Mr Fang Koh Look, 48 , the executive chairman of a consultancy firm, said he was pleased at the diversity of participants whose opinions would shape the future.
Dr Shashi also warned against merely planning for present threats.
He warned that, within 40 years, Singapore would become the ideal destination for climate change refugees in the area.
"Why not Singapore? We are safe. We are secure," he said.
As part of Total Defence Day, the Total Defence Exhibition at The Future of Us exhibition and S'pore Discovery Centre is jointly organised by Nexus and S'pore Discovery Centre. Both are open to the public.