Eleven countries have come together in an exercise to share information about maritime security challenges in the region.

Called South-east Asia Cooperation and Training (Seacat), the two-week maritime security exercise co-hosted by Singapore and the United States has the largest number of participants this year.

Myanmar and Sri Lanka are taking part in the annual exercise for the first time, joining the hosts and Bangladesh, Brunei, Indonesia, Malaysia, the Philippines, Thailand and Vietnam.

The exercise started on Aug 21 and will end on Friday.

Now in its 16th year, it is being conducted from the Republic of Singapore Navy's Changi Command and Control Centre at Changi Naval Base - the eighth consecutive year it has been held there.

The exercise aims to increase multilateral cooperation and information sharing among navies and coast guards across South and South-east Asia.

It features a series of tailored workshops, information exchanges and boarding operations at sea that rehearse scenarios relating to piracy, sea smuggling and maritime domain awareness.

In a press briefing at Changi Naval Base on Monday, Rear-Admiral Donald Gabrielson, commander of the US' Logistics Group Western Pacific based in Singapore, said that among other things, the skills learnt could be applied to a variety of threat scenarios, including terror threats.

Teams from different nations receive training at sea on seven boarding operations, where multinational liaison officers identify vessels suspected of illegal activities and alert naval forces out at sea to track and defuse these maritime threats, if necessary.

One of these operations was the compliant boarding of cargo ship Sunny Queen by a Republic of Singapore Navy (RSN) Accompanying Sea Security Team yesterday.

The RSN's Maritime Security Task Force, whose work includes daily patrols, boarding and escort operations in the Singapore Strait and sea lines of communications, was also involved in the exercise.

On Monday, Rear-Adm Gabrielson also talked about how longstanding international norms and agreements should be respected. This was in the light of concern over "a movement to upset the ability of many nations in the region to operate in a way... that we end up with a system that really is unilaterally advantaged and not fairly so".

He said: "It's important for everyone who has an interest in the region to do their part to understand that if the world does not come together to protect its own interests, then China will do everything it can to protect what it sees as its interests, at the cost of anyone else."

Rear-Adm Gabrielson did not rule out the possibility of North- east Asian countries being involved in future Seacat exercises, but said there were some logistical challenges.

"Having said that, the ability to share and operate on international maritime issues is always a good thing," he added.