Since the first Exercise Northstar in 1997, places such as shopping malls and MRT stations have been "attacked" over the years.
Yesterday, it was the Sports Hub's turn.
The exercises are designed to look and feel as real as possible as they are meant to gauge the readiness and coordination between national agencies in responding to major emergencies.
At about 1pm, a car exploded in the outdoor carpark, rocking the Sports Hub.
It was followed by another just metres away, shooting pillars of fire 10m into the sky. As thick black smoke billowed, a chemical agent was "released" into the stadium.
As people ran to the Kallang Wave Mall for safety, they were "attacked" by gunmen and dozens were felled.
The already chaotic scene at Stadium MRT station became worse as people tried to flee when an improvised explosive device was "found" in the stadium.
The scenarios were so realistic, it was not surprising that Exercise Northstar 9, which took place yesterday, frightened a number of people, including some of the 1,300 volunteers who role-played in the drill.
Mr Muhammed Amenuddin, 23, an operations specialist, was there with his two sisters and mother to play the role of spectators.
"I wanted to show them how the Singapore Civil Defence Force (SCDF) works in such a scenario," he said.
The SCDF led the joint exercise yesterday.
One of his sisters, four-year-old Nur Puteri, was the youngest participant.
She cried during the scenario when terrorists "attacked" the stadium.
"I cried because of the bad guys," she explained shyly.
Prime Minister Lee Hsien Loong, Deputy Prime Minister Teo Chee Hean and other members of the Cabinet witnessed the exercise that involved about 600 officers and 15 agencies, including the SCDF, Singapore Police Force, Ministry of Health and Singapore Armed Forces.
Commander of the 2nd SCDF Division, Lieutenant-Colonel Alan Toh, 47, who took part in the exercise, said it was important to have different organisations involved.
"The Sports Hub is new and is going to be a place for key events," he said.
"It is important to ensure that the various agencies are all familiar with the emergency response plan."
PM Lee said later: "We take it very seriously because terrorism is a very live problem for us in this region and in Singapore, we have to be very careful."
He also said that with the SEA Games taking place here next month, Singapore cannot afford to take chances.
"Major sports events sometimes attract attention and are a trophy target to attack. We must be quite prepared for the different things that could go wrong," he said.
Key aspects of Northstar 9
"Bombs" explode in two vehicles at a vehicle check station in the carpark, killing or seriously injuring officers. Police cordon off the area and evacuate people, as the Singapore Civil Defence Force (SCDF) works to fight the fires and rescue casualties.
Special Operations Command officers form the inner cordon, preventing unauthorised entry.
A terror suspect takes advantage of the chaos outside and enters the National Stadium, "releasing" a chemical agent causing civilians to cough, vomit and foam at the mouth. SCDF's Hazardous Materials team is deployed and it takes samples of the chemical agent.
A suspicious package, confirmed to be an improvised explosive device by the police, is also found in the stadium. A bomb-disposal squad neutralises this threat.
Frantic spectators enter Kallang Wave Mall, and some are "gunned" down by four gunmen disguised as shoppers. The police Anti-Swarming Team takes down the gunmen, after which SCDF personnel commence rescue operations.
A throng of people consisting of spectators from the stadium and shoppers from the mall rush towards Stadium MRT station, causing chaos. The crowd starts to build up, demanding to enter the station. Public Transport Security Command officers set up barricades and manage to disperse the crowd.
Decontamination of people who have been exposed to the chemical agent is done here.
Casualties are separated into categories based on their injuries and treated here.
This article was first published on May 10, 2015.
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