The raid against the Liberian-flagged ship Moscow University came 24 hours after pirates had taken the ship over and the crew locked itself in a safe room. The vessel is carrying 86,000 tons of crude oil worth about $50 million.
The special forces had been aboard the Russian anti-submarine destroyer Marshal Shaposhnikov, which rushed to the scene after Wednesday's attack. The special forces boarded a helicopter and rappelled down to the Moscow University, Rear Adm. Jan Thornqvist, force commander of the EU Naval Force, told The Associated Press.
Shots were fired during the raid but no one was injured, Thornqvist said.
Russian Defense Ministry spokesman Col. Alexei Kuznetsov said the pirates are being held aboard the tanker. Russian news agencies reported the death of one pirate during the raid, but Kuznetsov told AP that information was still being looked into.
The crew of the Moscow University had previously told officials they believed the pirates were trying to enter the engine room, Thornqvist said. The ship had been disabled and was not moving. Safe rooms, where crews seek shelter, are typically stocked with food, water and communications equipment and have reinforced doors that can only be opened from the inside.
The ship's owner, Novoship, said in a statement that the decision to free the ship was made knowing "that the crew was under safe cover inaccessible to the pirates and that the lives and health of the sailors was not threatened by anything."
Cmdr. John Harbor, a spokesman for the EU Naval Force, called the rescue "an excellent operation all around." He said the EU Naval Force had been working at a tactical level with the Russians, and that EU Naval Force personnel talked to the Russian crew by VHF radio. He said the EU had offered support to the Russians.
The attack occurred about 500 miles (800 kilometers) east of the Somali coast. The ship was not registered with the Maritime Security Center, said Harbor. The ship's route was from the Red Sea to China, the ship's owner said.
Novoship is a subsidiary of Sovcomflot, which is owned by the Russian government.
The fact that Russian special forces stormed the Moscow University shortly after it was taken over is in line with a trend by international military forces who are more aggressively combating piracy.
In February, Danish special forces prevented the hijacking of a ship after pirates had boarded it. Special forces from the Danish Absalon boarded the Ariella while the crew locked themselves in a secure room.
EU Naval Force ships are disrupting pirate groups and destroying their ships at a much higher rate than in previous years. US warships have fired back on pirates and destroyed their boats in several skirmishes in the last several weeks.
Pirates currently hold more than 300 hostages taken from ships attacked off East Africa in the last several months. Eleven suspected Somali pirates were indicted in US federal court late last month, but the international community has had problems formulating an accepted policy to try and jail pirate suspects.
Along with the increased pressure by international navies against pirates has come some criticism.
On Wednesday, a French prosecutor said a French rescuer was responsible for killing the skipper of a sailboat hijacked by Somali pirates during a rescue operation.
Chief prosecutor Hever Pavy in the western French city of Rennes said investigators found a French military bullet had killed Florent Lemacon in April 2009 when a special intervention team came to rescue his yacht, the Tanit, off the Somali coast.
Four other hostages were saved after a week on the hijacked ship. Three suspected pirates who survived the rescue operation are on trial in France.
