The navies of Singapore and Indonesia worked together to tackle a simulated terrorist threat to commercial ships in the Singapore Strait on Tuesday.

This scenario was played out as part of the 25th edition of the Singapore Armed Forces' longest-running bilateral exercise with a foreign military, Exercise Eagle Indopura. It started last Thursday and ends today.

In addition to maritime security drills, the navies executed advanced anti-surface and anti-air naval warfare manoeuvres, the Ministry of Defence (Mindef) said yesterday.

Speaking at the exercise's opening ceremony in Surabaya last Thursday, the Republic of Singapore Navy (RSN) Fleet Commander, Rear-Admiral Aaron Beng, said both navies need to continue working together to protect key maritime trade routes between Singapore and Indonesia.

He said that these waters are not just access points for terrorists, but also critical sea lines.

"The RSN and the TNI AL (Indonesian navy) have a long and deep history of cooperation. I am sure that we will continue to grow and deepen these bilateral interactions in the years to come," he said.

The exercise was conducted in three phases: the planning and coordination phase in Surabaya; the sea phase in the Java Sea as well as the Karimata and Singapore straits en route to the Republic; and the closing ceremony held on shore here.

The RSN deployed the Formidable-class frigate RSS Steadfast, Victory-class missile corvette RSS Vigour and Independence-class littoral mission vessel RSS Justice for the week-long exercise, which was first held in 1974.

The Indonesian navy participated with a Diponegoro-class frigate KRI Sultan Iskandar Muda, Fatahillah-class missile corvette KRI Fatahillah and a CN-235 maritime patrol aircraft.

Both navies conduct regular professional exchanges, exercises and port calls, said Mindef. They also collaborate on the multilateral Malacca Straits Patrol, which includes Thailand and Malaysia.

These interactions have enhanced the close ties between both navies' personnel, Mindef added.