"While operating within Vietnam's waters, in an area where Vietnam and Indonesia are delimiting our exclusive economic zones (EEZs) and 5.5 nautical miles north of the 2003 continental shelf delimitation line on April 27, Vietnamese fishing boat number BD 97916 TS and 14 fishermen on board were arrested and towed away at high speed by Indonesian ship number 381, causing the Vietnamese fishing boat to sink," Foreign Ministry spokeswoman Le Thi Thu Hang said in a statement Tuesday.

Hang said that the Vietnam Fisheries Resources Surveillance's vessel number 213 discovered the incident in time while performing its duties in the area, rescued two of the fishermen and demanded that the Indonesian ship leave Vietnamese waters.

However, the remaining 12 fishermen were taken into Indonesian waters.

Vietnam's Foreign Ministry has since sent a diplomatic note to the Indonesian embassy in Hanoi, asking Indonesia's authorities to verify the information, investigate to clarify the incident and not to let similar incidents happen in the future.

Vietnam has also demanded that Indonesia immediately release the crew of the sunk vessel, treat them humanely and provide adequate compensation for the Vietnamese fishing boat and for the fishermen.

Hanoi has also asked Jakarta to strictly abide by the provisions of the 1982 United Nations Convention on the Law of the Sea (UNCLOS), of which both countries are members.

The Vietnamese embassy in Indonesia has been instructed by the foreign ministry to urgently contact local authorities, verify information and take necessary measures to protect the country’s citizens.

Last year, Indonesia destroyed 86 Vietnamese fishing boats for allegedly illegally catching fish in its waters. Vietnam has several times called on Indonesia not to use violations against Vietnamese fishing boats and fishermen in a manner that goes against the strategic partnership between the two countries.