The sound of gunshots pierce the air and the crowd scatters as gunmen storm in. Moments later, the gunmen are swiftly subdued by the Army Deployment Force and elite commandos.

But multiple "terror threats" continue to appear islandwide, including a truck weaving through traffic in the Central Business District.

These were scenes that unfolded as part of a counter-terrorism exercise staged for the first time at the NDP yesterday, leaving many parade-goers on the edge of their seats and also having a deeper impression of the impact of terrorism.

The Singapore Armed Forces (SAF) and Home Team had joined forces to showcase Singapore's coordinated response to new security threats, even as they underscored the need to build trust and vigilance in the community. The 10-minute showcase was part of the parade's Dynamic Defence Display (D3) segment, which traditionally focused only on military might.

Said Lieutenant-Colonel Law Wei Shing, 36, who led the D3 segment: "If terror attacks were to hit our shores, we want to show that our security agencies are ready to counter them and bring normalcy back."

Members of the police's Emergency Response Teams and Rapid Deployment Troops brought the action to the audience in the stands. LTC Law said the use of gunshots, pyrotechnics and troopers in the seating gallery was to"give the audience a more immersive experience overall".

Said accountant James Chin, 62: "It was impressive. The speed at which they reacted and moved really showed that we are well-prepared ."

As paramedics tended to "casualties" and recovery efforts kicked in, the segment wrapped up with a united show of support in the aftermath of the attacks. A video recording also showed citizens turning up at blood donation drives, while others stepped up as volunteers.

Said Mr Michael James Parks, 22, who played the role of a gunman in the segment: "Working together is the best thing we can do as a nation. We cannot let any acts of terror break us apart."