Indonesia's navy says one of its patrol boats was rammed by two Vietnamese coast guard ships after intercepting an alleged illegal fishing boat.

The commander of Indonesia's Western Fleet, Rear Adm. Yudo Margono, said the Vietnamese fishing boat sank during the clash Saturday and Indonesia has detained 12 Vietnamese fishermen. Two others were rescued by Vietnam's coast guard.

Margono said in a statement Monday that the Vietnamese fishing vessel was detained in waters off Indonesia's Natuna island chain, which is the southernmost reaches of the South China Sea. Indonesia calls the waters the North Natuna Sea.

Video purportedly shot from the Indonesian vessel shows a Vietnamese patrol boat colliding with it as Indonesian seamen shout out insults such as "dog," ''pig" and "you die."