The Indian navy says that one of its warships in the Gulf of Aden has destroyed a ship belonging to pirates operating off the coast of Somalia. The INS Tabar opened fire on a pirate "mother ship" after it came under attack, a government statement said. There has been a surge in piracy incidents off Somalia. The Saudi-owned Sirius Star supertanker is currently anchored off the Somali coast after the vessel and its 25 crew were seized by pirates.

Vela International, operators of the Sirius Star, told the BBC no demands had yet been received from the pirates. The company also said all the crew were safe. The biggest tanker ever hijacked, Sirius Star is carrying a cargo of 2m barrels - a quarter of Saudi Arabia's daily output - worth more than US$100m (£67m).

India is among several countries are already patrolling the Gulf of Aden, one of the world's busiest shipping lanes which connects the Red Sea and the Indian Ocean.
  
Fire broke out on the vessel and explosions were heard, possibly due to exploding ammunition that was stored in the vessel.  Indian naval statement  said the Tabar spotted a pirate vessel while patrolling 285 nautical miles (528km) south-west of Salalah in Oman, on Tuesday evening. When it demanded the vessel stop for investigation, the pirate ship responded by threatening to "blow up the naval warship if it closed on her", the statement said.

 

The navy said the pirates on board were armed with guns and rocket propelled grenade launchers. They threatened to blow up the INS Tabar and then fired on it. The Indians say they retaliated by opening fire and that there was an explosion on the pirate vessel, which sank. "Fire broke out on the vessel and explosions were heard, possibly due to exploding ammunition that was stored in the vessel," the Indian navy said.

 

Some of the pirates tried to escape on two speedboats - the Indian sailors gave chase but one boat was later found abandoned, while a second boat escaped.

The Tabar has been patrolling the Gulf of Aden since 23 October, and has escorted 35 ships safely during the "pirate-infested waters", the statement said. Last week, an helicopter-borne Indian marine commandos stopped pirates from boarding and hijacking an Indian merchant vessel. On Tuesday, a cargo ship and a fishing vessel became the latest to join more than 90 civilian vessels attacked by the pirates this year.

A 25-crew cargo vessel transporting wheat to Iran was attacked in the Gulf of Aden while contact was lost with the crew of 12 on the fishing boat. Piracy in the area is estimated to have cost up to $30m in ransoms so far this year, according to a recent report by a UK think-tank. The pirates who seized the Sirius Star are a sophisticated group with contacts in Dubai and neighbouring countries, says the BBC Somali Service's Yusuf Garaad. Much of their ransom money from previous hijackings has been used to buy new boats and weapons as well as develop a network across the Horn of Africa, he adds.

The hijackings off the coast of East Africa and the Gulf of Aden - an area of more than 1m sq miles (2.6m sq km) - make up one-third of all global piracy incidents this year, according the International Maritime Board.

Somalia has not had a functioning national government since 1991 and has suffered continuing civil strife.

Shipping companies are now weighing up the risks of using the short-cut route to Europe via the Suez canal.