"The Rabikh vessel, sailing some 30 miles from the Neustrashimy, was attacked by several high-speed pirate boats," Dygalo said.
The Neustrashimy entered waters off the Somali coast in late October. Somali pirates have attacked around 60 ships so far this year, resulting in the seizure of around 30 vessels. The East African nation has been without a functioning government since 1991 and has no navy to police its coastline.
A Ukrainian ship, the Faina, carrying tanks and heavy weaponry was seized by Somali pirates on September 25. The pirates have demanded an $8-million ransom in exchange for the release of the Ukrainian-Russian crew.
The Faina's Russian captain died of a heart attack after the vessel was seized. The pirates holding the ship have threatened to kill the hostages if a military operation is launched against them. Food and water supplies on board the vessel, which has been held for seven weeks, are reportedly running critically low.
NATO and the EU have recently announced plans to increase their naval presence in the Gulf of Aden. About 20,000 vessels pass through the region annually.
In early June, the UN Security Council passed a resolution permitting countries to enter Somalia's territorial waters to combat "acts of piracy and armed robbery at sea."