Somali and Yemeni pirates' attempt to hijack for ransom Indian cargo vessels sailing off the Somalia coast has once again been thwarted by an Indian warship.

INS Delhi, a guided missile destroyer, was assisting the merchant ships that were sailing through the Gulf of Aden when the armed sea brigands made the attempt on one of the 12 ships in the formation on Sunday, a Navy spokesperson said in New Delhi on Monday.

The pirates' boat was intercepted by the Indian warship, which deployed a helicopter with marine commandos, who seized a cache of weapons and offloaded the fuel and left their boat adrift, the spokesperson said.

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This was the 16th piracy attack on merchant vessels in the Gulf of Aden that was prevented by the Indian warships that have been deployed there since October 2008.

"On September 5, 2010, while on anti-piracy mission in the Gulf of Aden, Indian Naval Ship 'Delhi' successfully neutralised a pirate boat, while escorting merchant vessels," he said.

The piracy attempt took place at 1215 hours on the International Recommended Transit Corridor (IRTC) in the Gulf of Aden, he said.

INS Delhi, which is the 21st Indian warship to be on anti-piracy mission, has been deployed in that area since mid July.

It was escorting Jag Ratan and 11 other vessels. "At about 1215 hours, in a position 180 km north of the Somali coast in the International Recommended Transit Corridor, a boat was detected approaching the formation at high speed," the spokesperson said.

INS Delhi immediately and repeatedly called the boat on Mercantile Marine Radio to abandon its path and turn away, but the boat failed to respond to these calls.

"Sensing that the boat may pose a risk to the ships being escorted, INS Delhi safely manoeuvred the formation of merchant ships away and intercepted the boat," he said.

A Chetak helicopter, with marine commandos on board, was launched to provide aerial cover to the merchant vessels and the boat 'Bareeda' was successfully intercepted, forced to stop and boarded by the marine commandos from INS Delhi.

"On investigation, a cache of arms and several fuel drums and ship boarding equipment were found. There were seven Somali and one Yemeni national as part of the speed boat's crew. The men were disarmed and excess fuel on the boat was disposed of by the boarding commandos team," he said.

Since the Indian Navy started its anti-piracy operations, it has escorted over 1,200 cargo ships and not a single vessel under its escort has fallen prey to pirates, the spokesman added.