Although thwarted, the plans for a rocket attack against Singapore from Batam show that the threat to our security is drawing ever closer ("Plot to attack Marina Bay with rocket from Batam foiled"; last Saturday).

Arresting the six terror cell members involved, whether they are aligned with the Islamic State in Iraq and Syria (ISIS) or not, will not remove this threat. For every member captured or killed, more will replace him.

The recent terror attacks worldwide, such as in France, Germany and Belgium, show that even with the tightest security measures in place, incursions will occur. We, therefore, need to be more than just vigilant. We need to address aerial threats originating from Batam or nearby waters differently.

Singapore urgently needs an anti-missile defence system, such as the Iron Dome deployed so effectively by the Israelis against incoming rockets from southern Lebanon. Indeed, according to the Israeli Defence Forces, the Iron Dome missile defence system had a 90 per cent success rate in intercepting rockets.

In Singapore, just one rocket will cause unthinkable damage and untold casualties.

We need to outsmart and outpace terrorists with technology and intelligence to keep our country safe.

Douglas Chua Hock Lye