Deputy Prime Minister Teo Chee Hean's call for unity and harmony among Singaporeans is a timely one ("Singaporeans must 'stand united in face of terror threat'"; Monday).

The recent spate of terror attacks in Europe and the Middle East and the growth of extremism within our region are troubling reminders of the serious threats facing Singapore.

Lone-wolf attacks, which are unpredictable and hard to detect, mean that the chances of an attack occurring here are higher than ever before.

Singapore's racial and religious harmony is not only a trait to be safeguarded, but also a powerful tool to be wielded against the corrupting influences of those who seek to stoke tensions and divide us.

As Communications and Information Minister Yaacob Ibrahim pointed out, the strengthening of our nation's cohesiveness is an ongoing process that must never be taken for granted.

Societies are becoming increasingly polarised, with emotions and prejudices clouding people's judgment and inflaming tensions. The rise of populists, such as United States presidential candidate Donald Trump, shows how easy it is to exploit such fears and further deepen fault lines between communities distrustful of one another.

Even as we celebrate our nation's racial and religious diversity, we must continue to prioritise our common national identity as Singaporeans.

Regardless of individual differences in opinions or beliefs, the stability and security of our nation as a whole should always be foremost in our minds.

The world may seem more divided than ever before, but let us work together to keep our Singapore sampan in more peaceful waters.

Dhevarajan Devadas