For two days, 27 military and security officers from Singapore and Indonesia gathered behind closed doors to find ways to tackle growing threats in the region, such as returning fighters trained by terror organisations like the Islamic State in Iraq and Syria (ISIS).
Four simulated challenges, involving, for example, gunmen attacking a shopping mall or vehicles ramming into pedestrians, were created for them to discuss and overcome.
Held at Sheraton Towers hotel, the counter-terrorism table-top exercise, which did not involve actual drills, was the first between the Singapore Armed Forces and a foreign military.
The SAF-TNI (Indonesian National Defence Forces) counter-terrorism table-top exercise ended yesterday. Officers who took part included personnel from the air, land and sea units, special operations forces, the Singapore Police Force and the Indonesian national counter-terrorism agency.
A concern of both sides was fighters involved in overseas terror operations returning to the region, said the leader of the SAF delegation, Colonel Lim Kok Hong, who heads the SAF Current Operations Group.
"They can choose to go into any of our countries, and the more information we share... the better we would be in understanding where they are likely to go," he said.
The Singapore Terrorism Threat Assessment Report released in June said that the Republic had been specifically targeted in the past year and the regional threat has heightened. It added that with ISIS losing ground in Syria and Iraq, the flow of returning fighters to South-east Asia may increase.
Col Lim highlighted a key learning point: "We find that the government agencies and armed forces have different areas of responsibility, but we must be very coordinated in the way we face the threat of terrorism at the seams, where the responsibilities meet."
He added that both Singapore and Indonesia are "very serious and interested" in making this exercise a regular one in the future.
The last time both sides held a joint counter-terrorism exercise was in 2012. It was a three-day event, involving 150 special forces personnel.
The leader of the Indonesian delegation was Colonel Achmad Budi Handoyo, the senior staff officer for the Joint Exercise Office of TNI headquarters.
A flagship exercise between the two infantries, Exercise Safkar Indopura, came to an official close on Nov 20, while a combined fly-past over the Marina Bay area witnessed by top leaders from both sides took place in September.