NEW DELHI  As negotiations started for the release of a Saudi-owned supertanker seized by pirates off Somalia, the Indian Navy said on Wednesday that one of its warships fought a battle at sea with would-be hijackers in the Gulf of Aden, sinking one suspect vessel and forcing the pirates to abandon a second as they fled.

The drama on the night-time waters of the Indian Ocean late Tuesday underscored the growing international concern at the audacity with which armed pirates, mostly based in Somalia, range across vast areas of the Indian Ocean and the Gulf of Aden, attacking at will.

The enormous Saudi-owned supertanker, Sirius Star, remained at anchor off the coast of Somalia on Wednesday, but there was no immediate word on the status of negotiations for its release.

In Rome, Prince Saud al-Faisal, the Saudi foreign minister, confirmed that the owners of the Star “are negotiating on the issue” and were “the final arbiter of the issue”, despite the Saudi government’s official opposition to such discussions with “pirates, terrorists or hijackers,” according to news reports. But he did not elaborate.