Hitting Singapore from Batam would have required a military- grade rocket and complex calculations, said a military observer.

Though it is not known what kind of rockets the suspects planned to use, weapons and equipment editor Kelvin Wong of military publication IHS Jane’s told The Straits Times they would likely have needed a military-grade rocket able to travel the distance of around 25km between the Indonesian island and Singapore. If they were building their own rocket, fine calculations would have been required.

… But S. Rajaratnam School of International Studies research fellow Wu Shang-su highlighted the possibility of attackers launching a rocket from a boat nearer to Singapore, possibly putting Marina Bay within range.