A week after saving two merchant vessels from sea pirates, the Indian Navy has sunk a pirate 'mother ship' during a fierce battle in the Gulf of Aden near the Horn of Africa.

Indian Navy spokesperson on Wednesday said its stealth frigate INS Tabar, currently deployed in the Gulf of Aden for anti-piracy surveillance and patrol operations, had successfully sorted out the pirates last evening 285 nautical miles south west of Salalah in Oman.

Giving details of the operation, the spokesperson said the frigate encountered the pirate vessel with two speed boats in tow.

"This vessel was similar in description to the 'Mother Vessel' mentioned in various piracy bulletins. INS Tabar closed in on the vessel and asked her to stop for investigation," he said.

Despite repeated calls from INS Tabar, the pirate vessel's crew threatened to blow up the naval warship if it sailed closer.

Pirates were also seen roaming on the upper deck of this vessel with guns and rocket propelled grenade launchers and they continued the threats and subsequently fired upon INS Tabar, he said.

The warship retaliated in "self-defence" and opened fire on the mother vessel of the pirates.

"As a result of INS Tabar's guns booming, fire broke out on the pirate vessel and explosions were heard, possibly due to exploding ammunition that was stored on the vessel," the spokesperson said.

Almost simultaneously, Indian Navy said, two speed boats were observed breaking off to escape. The ship chased the first boat, which was later found abandoned. The other boat made good its escape into darkness, it added.

INS Tabar was deployed on anti-piracy mission in the Gulf of Aden since November 2.

Western Naval Command has been controlling the anti-piracy operation since October 23 when the government ordered the Navy to deploy a warship in Gulf of Aden with the mandate to save Indian merchant vessels distressed by pirates.

Since deployment, INS Tabar has successfully escorted 35 ships, including a number of foreign-flagged vessels on receiving their request, safely during their transit through pirate-infested waters of the Gulf of Aden, apart from throwing back pirates, who were attempting to hijack an Indian and a Saudi vessels on November 11.

The Indian action against pirates comes in the wake of Japanese ship M V Stolt Valor with 18 Indian crew members being hijacked from Gulf of Aden by Somalian pirates on September 15 and being held in captivity for over two months.

The vessel and the crew were released by the pirates on November 16 after the Japanese shipping company reportedly paid a huge ransom.