NAIROBI, Kenya (AP) - A supertanker carrying about $160 million

of crude oil from Iraq to the United States is believed to have

been hijacked by Somali pirates, officials said Monday, the latest

high-value bargaining chip for the sea bandits.

Similar seizures of oil supertankers in the waters off the coast

of lawless Somalia have yielded ransoms as high as $5.5 million.

A South Korean navy destroyer was rushing toward the supertanker

but its highly volatile cargo prevents crews from carrying guns on

board or even lighting cigarettes while on deck.

The South Korean-operated 300,000-ton Samho Dream is believed to

have been seized Sunday when the South Korean navy received a call

from the vessel saying three pirates had boarded it and then lost

contact.

At the time, it was about 930 miles (1,500 kilometers) southeast

of the Gulf of Aden. It has 24 crew - five South Koreans and 19

Filipinos.

A maritime analyst doubted the South Korean warship would launch

an assault on the pirates believed to be holding Samho Dream

because such action would put the crew at great risk.

"The reason why an assault is an extremely hazardous is you

have to be able to suppress the pirates and take control back as

fast as possible. If you don't take control fast, there is a

greater risk to the crew," said Graeme Gibbon Brooks of Dryad

Maritime Intelligence in Britain.

The South Korean warship was ordered to move toward Somali

waters where the supertanker was expected to be taken. The

destroyer will need a little over a day to catch up to the tanker,

said Kim Young-sun, a spokesman of South Korea's Foreign Ministry.

"We're doing this in cooperation with the ships of our

allies," Kim said on Monday, declining further comment citing

efforts to "ensure the safety of the crewmen and the success of

possible negotiations."

Previously, when Somali pirates have captured supertankers,

naval forces patrolling the Gulf of Aden have only moved close to

the pirate lairs where the vessels have been anchored to monitor

them until they are released.

This was the case when a a Greek-flagged oil supertanker was

seized in November last year and a Saudi supertanker was hijacked

in November 2008.

The vessel operator said Monday it had lost contact with the

ship. "We currently cannot reach the Samho Dream's captain," Cho

Yong-woo of Busan, South Korea-based Samho Shipping, told The

Associated Press. He said the ship is owned by a Singaporean

company.

The tanker was sailing from Iraq to the U.S. state of Louisiana,

South Korea's Foreign Ministry said.

The Samho Dream had no security detail because Somali pirates

were believed to be inactive in the area where the tanker was

seized - several hundred miles (kilometers) from Somalia, said Cho.

The waters surrounding the Horn of Africa nation, including the

Gulf of Aden, which connects the Red Sea and the Indian Ocean, are

known to be among the world's most dangerous. An international

flotilla, including warships from the United States, the European

Union, NATO, Japan and China, has been patrolling the area to

protect the vital sea lane that links Asia to Europe.

But pirates have also shown an ability to strike farther afield,

on the high seas.

The U.S. 5th Fleet, however, said in a statement Monday that the

distance Somali pirates are willing to go to capture ships shows

their desperation and is a sign of the success of a multinational

effort to police the vast Gulf of Aden.

"The idea of getting their share of a ransom payment also leads

them to become more desperate to achieve the goal of capturing a

merchant vessel to bring back to the pirate anchorages off the

coast of Somalia to await further ransom payments," said the U.S.

5th Fleet statement. "It's the same desperation that now leads to

numerous pirate action groups spread out all over the Arabian

Sea."

Brooks also said the attack was not an indicator Somali pirates

are specifically seeking to hijack supertankers because "piracy is

a crime of opportunity."

"What we are seeing is the usual activity during the

inter-monsoon period (between March and May)," said Brooks. "This

window is where they (pirates) are busiest simply because the

weather allows it."

The Samho Dream can carry approximately 260,000 tons of crude

oil, said an employee at Samho Shipping, who asked not to be named

due to the sensitivity of the issue.

That would be about 1.9 million barrels, which at current oil

prices is worth approximately $160 million.

Valero Energy Corp., an oil and gas refining company based in

San Antonio, Texas, said it owns the cargo on board the tanker, but

could not confirm the hijacking.

"We've had reports to that effect, but there's been no official

confirmation," said Bill Day, a spokesman for Valero. But, he

added, "Everything points to that."

Also on Monday, the Dutch Defense Ministry said one of its Navy

frigates freed a German merchant ship and 15 crew off the coast of

Somalia after the Dutch ship's helicopter fired on the captured

freighter's bridge and marines slid down ropes onto the German

ship, the mv Taipan.

The marines arrested 10 pirates who seized the ship Monday

morning. The German ship's crew members had locked themselves into

a secure area of the ship and were unharmed. One Dutch marine was

slightly injured during the boarding.

The statement said the German container ship resumed its voyage.

Somalia has not had a functioning government since 1991 and its

lawless coastline is a haven for pirates. At least 17 ships and

more than 240 crew are believed to be currently held by pirates off

the coast of Somalia, according to various officials.

Multimillion-dollar ransoms have become a way to make money in the

impoverished nation.