The sea, however, has been threatened with potential instability from frequent piracy, while sovereignty disputes over islands are becoming more complex.

Confidence-building measures were rarely mentioned prior to the 1980s. Joint patrols had not been widely discussed, and there was no real consensus among concerned states around the East Sea.

Specialised maritime forces of regional countries have recently been conducting joint patrols between naval forces and coast guards, especially those of ASEAN member countries. This is considered an important measure to build trust and also contributes to maintaining a peaceful and stable environment.

According to figures from the International Maritime Bureau for the first quarter of 2015, there were 54 piracy cases around the world, of which more than half were in Southeast Asia. Indonesia had the most pirate attacks, with nearly 40% of all cases. Vietnam was also witnessing an increase in piracy, with many cases involving strange vessels using illegal weapons to attack Vietnamese fishing boats.

According to the Vietnam Register Quality and Safety Management System Certification Centre at Vietnam Registry, maritime security in general and piracy in Southeast Asia in particular have become more complicated in recent times. Representatives from the centre have said that the common method of pirates in the past was to attack ships to steal property and belongings, and also to attack oil vessels, but they are now focused on kidnapping people for ransom.

According to the Vietnam Maritime Administration, in Asia in January 2017 there were six armed robberies against vessels, of which four were successful.

To cope with the situation, ASEAN member countries boosted cooperation in joint patrols, with Vietnam having conducted specialised patrols with Thailand since 1998. Such patrols have contributed to maintaining peace and stability in their border waters and created the conditions for fishing fleets from both countries to exploit marine resources. Joint patrols of functional forces have also contributed to building trust, enhancing mutual understanding, and sharing information, so the waters of the Gulf of Thailand can be jointly managed.

Apart from Thailand, Vietnam and Cambodia regularly hold joint patrols involving specialised forces from the two countries, contributing to maintaining security and order in border waters.

Annual joint patrols between ASEAN countries have contributed to ensuring maritime safety while reducing the risk of potential conflict in the East Sea. With maritime and island sovereignty disputes not yet fully resolved, cooperation in joint patrols is seen as an effective confidence-building measure. Experience has shown that joint patrols contribute to promoting a peaceful and stable maritime environment and to deterring the actions of pirates in the East Sea./.VNA