The captain of a U.S.-flagged, Danish-owned container ship hijacked by pirates in the Indian Ocean is being held hostage on the ship's lifeboat, a crew member on the vessel told CNN on Wednesday.

Pentagon officials said the crew appeared to have retaken control of the vessel, the 17,000-tonne Maersk Alabama, after the hijacking.

The second mate of the ship, Ken Quinn, said in a telephone interview that the other members of the 20 crew on the ship were trying to negotiate the captain's release by offering food.

They want to hold our captain for ransom, and we are trying to get him back, Quinn said. He is in the ship's lifeboat.

Quinn said all four pirates were on the lifeboat, after sinking their own boat when they seized the container vessel.

The crew took one pirate hostage and held him for 12 hours. They then released that pirate to the other pirates in exchange for the captain, but this did not work, Quinn told CNN.

We're offering food but it's not going too well.

Maritime officials said the Maersk Alabama had been carrying food aid for Somalia and Uganda to Mombasa from Djibouti when it was seized far out in the Indian Ocean in an escalation in attacks off the lawless Horn of Africa nation.

Maersk Line, the U.S. subsidiary of Denmark's A.P. Moller-Maersk that owns the ship, said it could not confirm the vessel was back under the control of its crew.

A Pentagon spokeswoman, Army Lieutenant Colonel Elizabeth Hibner, said she understood at least four pirates boarded the ship at first. She said it was not clear how the crew may have retaken the ship.

There was no suggestion anyone had been harmed, a second Pentagon official, who asked not to be named, told Reuters.

The U.S. Navy destroyer Bainbridge was en route, Hibner said. Details on how far away it was were not immediately available. Earlier, a Pentagon spokesman said it was probably correct the nearest U.S. warship was hundreds of miles away.

A.P. Moller-Maersk said the Maersk Alabama had been attacked by pirates about 500 km (300 miles) off Somalia and was presumed hijacked. It said it had 20 American crew on board.

Maersk Line president and chief executive John Reinhart told reporters he could not confirm the crew had retaken control.

A lot of speculation is going on. I believe it is premature to comment on that, he said on a conference call, adding that he had received a cell phone call from the crew at about 11 a.m. EDT (4:00 p.m. British time) saying they were all safe.

THEY HAVE NO WEAPONS

He said company protocol advised the U.S. sailors not to attempt to retake the ship once hijackers were on board.

Once boarded, the crew has safe rooms and they are not to take on active engagement because they have no weapons. It would be a risk to their lives, Reinhart said. It would be first time Somali pirates have seized U.S. citizens, if only briefly.

The Maersk Alabama is owned and operated by Maersk Line, a Norfolk, Virginia-based subsidiary of A.P. Moller-Maersk and the world's biggest container shipper.

Among the ship's cargo were 400 containers of food aid, including 232 containers belonging to the U.N.'s World Food Programme that were destined for Somalia and Uganda.

In the latest wave of pirate attacks, gunmen from Somalia seized a British-owned ship on Monday after hijacking another three vessels over the weekend.

In the first three months of 2009 just eight ships were hijacked in the strategic Gulf of Aden, which links Asia, the Indian Ocean and the Red Sea to Europe via the Suez Canal.

Last year, heavily-armed Somali pirates hijacked dozens of vessels, took hundreds of sailors hostage -- often for weeks -- and extracted millions of dollars in ransoms.

Foreign navies sent warships to the area in response and reduced the number of successful attacks.

Uganda Somalia