Russian forces freed a hijacked Russian oil tanker in a helicopter-backed operation on Thursday, rescuing its crew and, according to one report, killing a Somali pirate.

Pirates on Wednesday hijacked the MV Moscow University in the Gulf of Aden with its 23-member crew and a cargo of crude oil worth $52 million.

The European Union's naval force said the Russian warship Marshal Shaposhnikov had sent in a helicopter that returned fire after being shot at by pirates.

'Eventually the pirates surrendered and a boarding team from the Marshal Shaposhnikov arrived on board the tanker, captured all the pirates and freed the crew. All the crew are safe and well,' and EU naval statement said.

However the state-run RIA news agency, citing an unnamed Russian navy official, said the Russians had killed one pirate and captured 10.   

A spokesman for Russia's Foreign Ministry, Igor Lyakin-Frolov, confirmed that some pirates had been captured, but said it was unclear if there were casualties among them.   

'The captured pirates will most likely be handed over to the authorities of countries in the region,' he told Reuters. The tanker would most likely continue on its planned voyage to China, he said.

Somali pirates are still able to seize ships despite the presence of an international fleet of warships in the busy shipping lanes linking Europe with Asia. Shipowners and insurers have paid out tens of millions of dollars in ransoms.

The successful rescue operation will please the Kremlin, which has been seeking to revive Russia's naval muscle despite limited resources.

Russia has been sending warships to patrol and protect Russian crews and cargoes off the Horn of Africa since the hijacking of the Ukrainian-owned cargo ship MV Faina in 2008 and the death of its Russian captain. The Faina was carrying a cargo of 33 tanks.
- Reuters