The US cargo ship captain taken captive by Somali pirates has been freed without injury after days of ordeal, CNN reported on Sunday night.

US soldiers aboard warships launched a raid on the lifeboat in which the four pirates held US cargo ship captain Richard Phillips, killing three hijackers and taking one in custody.

At least three US warships including the destroyer USS Bainbridge were present when the navy operation began.

The captured pirate could face life imprisonment as piracy and hostage-taking carry life sentences under US law..

FBI spokesman John Miller said the situation of the hijacker "in military custody right now ... becomes more of a criminal issue than a military issue.''

The USS Bainbridge reached the troubled waters on Thursday to begin the five-day high seas standoff with the pirates, who had taken Phillips hostage in a lifeboat the day before.

The pirates on Wednesday briefly took the Danish-owned cargo ship Maersk Alabama with the crew of 21 Americans on board.

The cargo ship, carrying food aid destined for Somalia and Uganda, was attacked about 500 km off Somalia's coast.

Captain Richard Phillips allowed himself to be taken hostage in exchange for the freedom of the 20 others. The 53-year-old captain was then taken to the lifeboat seized by the pirates from the US-flagged cargo ship.

Before the rescue operation, Somali elders tried to negotiate the release of the US captain, but failed to persuade the pirates, who insisted on a ransom of 2 million US dollars and departure with their captive.

The Maersk Alabama docked at the port of Mombasa, Kenya, on Saturday night. Mombasa is a vital hub for receiving food assistance for Sudan, Uganda, Rwanda, Somalia and Kenya.

Somali pirates have stepped up their attacks in recent weeks after a brief lull. The Maersk Alabama was the sixth ship attacked by pirates in the past week.

Pirates typically hold the ships and crews until large ransoms are paid by the shipping companies. The attacks are threatening to destabilize one of the world's busiest shipping lanes.

(Xinhua News Agency April 13, 2009)