WASHINGTON – U.S. forces today boarded a North Korean freighter in the North Arabian Sea loaded with 12 short- to medium-range missiles along with other missile parts, U.S. officials announced.

U.S. intelligence had tracked the North Korean-flagged ship, the So San, since it left the North Korean port of Nampo about three weeks ago, officials said. It was first stopped and boarded yesterday by a Spanish navy warship. The crew on the freighter had painted over the North Korean flag on its side once the ship entered the Arabian Sea.

The intended destination of the missiles is unknown. The ship’s manifest declared that it was carrying cement mix to an undisclosed location. However, when U.S. and allied naval forces inspected it, they found several crates containing North Korean Scud missiles. A U.S. Navy explosives team boarded the ship to secure the missiles. U.S. officials said the 12 Scud missiles were hidden beneath concrete.

U.S. officials said the false manifest and the crew’s refusal to reveal the ship’s destination was sufficient reason to seize the ship.

“The ship was stopped on Monday by Spanish authorities, who stopped it in the Arabian Sea about 600 miles from the Horn of Africa,” an official told Reuters news agency. “It was believed to be bound for Yemen.”

Defense Secretary Donald Rumsfeld said at a news conference two weeks ago that North Korea was the world’s “single biggest proliferator” of ballistic missiles and a “danger to the world.”

“This is an issue of concern,” Bush administration spokesman Sean McCormack told the Associated Press. “We are working with other governments to figure out the next step.”

McCormack said the immediate tasks were to deal with the crew, identified as from North Korea, and to secure the ship.

Iraq used Scuds to attack Israel during the 1990-91 Persian Gulf War. They are believed to be capable of carrying biological warfare agents.

There is no evidence that North Korea has sold Scuds to Iraq recently, though Iraqi Scuds are based on an original design by North Korea. North Korea is known to have sold Scud missiles to Pakistan, Syria, Egypt, Iran, Libya and Yemen.

Officials said the shipment did not appear to be headed for Iraq. However, a senior administration official told the Associated Press that although the ship was headed for Yemen, it was unclear whether it and the missiles on board had another destination beyond that.

Yemen has been identified by the United States as a nation that has harbored terrorists, although its government has been an ally of the United States in the war against global terrorism. Yemen’s port of Aden was the site of the October 2000 attack on the USS Cole by terrorists, which killed 17 sailors.

Yemeni officials have claimed that their past purchases of Scud missiles for self-defense purposes were perfectly legal. U.S. officials said that the Scuds would be within range of U.S. troops stationed in Djibouti should any of the missiles fall into the wrong hands.

Tensions between the U.S. and North Korea have worsened in recent weeks, as North Korea acknowledged it has an ongoing uranium enrichment program, in violation of a 1994 agreement with a coalition of countries, including the United States. Under that agreement, the Korean Economic Development Organization, funded by the United States, South Korea, Japan and the EU, was building a light-water nuclear reactor for North Korea and providing fuel oil, in exchange for a vow that Pyongyang would halt its own nuclear programs.

President Bush has called North Korea part of an “axis of evil,” along with Iraq and Iran.

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