The circumstances surrounding the release of the Tai Yuan 227 were unclear but the owner of the ship had received a call from the master saying it had been freed, although he did not know why, according to a statement from the force. The EU had not had direct contact with the ship.
The vessel has 28 crew onboard from China, Vietnam, the Philippines, Kenya and Mozambique. It was attacked on May 6, 2010, northeast of the island nation of the Seychelles.
The crew were provided with fresh food and water by a U.S. warship after the release. The vessel is currently sailing away from Somalia.
Meanwhile, NATO said a Danish warship rescued two men who escaped from pirates off East Africa's coast.
The alliance said the men were among several crew members who attempted to shake their captors two days after their ship, the MV Beluga Nomination, was hijacked. The attempt to overwhelm the pirates failed, but the two seamen, a Ukrainian and a Filipino, managed to escape in one of the ship's life boats.
NATO said the pair spent two days at sea before being picked up by the HDMS Esbern Snare on Friday.
The rest of the crew remains aboard their ship — now anchored off the Somali coast — where they await rescue or ransom.
In South Korea, the government said it would bring home a ship captain shot by Somali pirates during a rescue operation last week.
A Foreign Ministry official said an air ambulance carrying the captain will arrive in Seoul on Saturday evening and the captain will get more medical treatment. The official asked not to be identified because he wasn't authorized to speak to media. He didn't elaborate about the captain's condition.
The captain was the only crew member wounded during last week's raid by South Korean commandos on a hijacked Korean freighter in the Arabian Sea.
The commandos rescued all 21 hostages, including the captain, while killing eight pirates and capturing five others. South Korea plans to bring the five pirates to the South for prosecution.