SINGAPORE - Singapore needs to be vigilant against those who seek to mount insidious information campaigns to influence segments of Singaporeans for their own ends, said former president Tony Tan Keng Yam on Tuesday (Nov 28).

"Singapore cannot tolerate attempts by foreign countries or entities to manipulate our people's sentiments," Dr Tan told 800 diplomats and students in his first public lecture since his six-year presidential term ended on Aug 31, 2017.

There may be attempts by external forces to divide Singapore along racial and religious fault lines, he warned as he pointed to how foreign influences like religious extremism are already worsening societal divisions in other countries.

In the face of such attempts, the ties that bind Singaporeans as one people are vital, he said at the annual S Rajaratnam Lecture organised by the Ministry of Foreign Affairs.

"At the end of the day, a successful foreign policy also requires strong domestic support at home. We have to close ranks and stand firm on issues that will have a significant impact on Singapore's interests," he added.

In a 30-minute lecture titled "The domestic context of Singapore's foreign policy", Dr Tan made the case that for a small country like Singapore, domestic and foreign policies are inextricably linked.

Singapore must not shy away from standing up for its vital interests, even if it leads to bilateral relations turning sour for a while, he stressed.

And Singaporeans need to have the confidence to stand together as a nation and weather such turbulence when it comes, he said.

These include issues concerning sovereignty like the dispute over Pedra Branca, and honouring of important international agreements such as the terms of the Water Agreements and the Points of Agreement with Malaysia, said Dr Tan, who is now honorary patron at the Singapore Management University.

"Each time, each test, we have stood firm," he added.

Singapore also needs to stay cohesive and resilient to succeed.

But the spread of fake news and misinformation threatens Singapore's domestic and foreign policy alike.

Big and small states have realised they can use misinformation to undermine the will and resolve of nations they have problems with, Dr Tan noted.

And smaller players can manipulate social media to undermine the resilience of target countries at little cost, he added.

The technique is new but the goal is an age-old one: "They seek to divide a country against itself," he said.

Singapore is vulnerable as one of the most Internet-connected societies in the world and one of the most diverse nations on earth.

To guard against this threat, Dr Tan urged people not to take information at face value.

"The next time you read a foreign policy commentary or op-ed, ask yourself who stands to benefit from the proposed course of action," he said.

Singaporeans also need to be well-informed and understand not just a diversity of views but also the trade-offs that come with each policy position, he added.

For instance, greener policies may cost businesses more, but would help manage climate change which would otherwise hit Singapore hard.

Also, training officers from other countries may divert resources from local policies, but will go a long way in generating goodwill for Singapore, said Dr Tan.