WASHINGTON (AP) _ Secretary of State Colin Powell said Wednesday he had permitted a ship carrying North Korean missiles to proceed on to Yemen with the weapons after Yemeni President Ali Abdallah Salih assured him it was the last such delivery.

Senior administration officials disputed some cable television reports that the missiles were intended for delivery to a terrorist state.

The officials, speaking on condition of anonymity, said Yemen had contracted for the Scud missiles before the Arab country pledged last year to stop importing dangerous technology from North Korea.

Powell called North Korea ``one of the great proliferators on the face of the earth,'' and said the United States had been trying to make the case worldwide that it posed dangers.

``But at the same time we recognized it (the shipment) was going to a country we have good relations with,'' Powell said.

But after a ``flurry of phone calls'' and assurances from Salih that ``this would be the end of it,'' Powell said the shipment was permitted to go to Yemen.

He said Salih had assured him not only that it was the last delivery of missiles from North Korea, but that the missiles were intended for Yemen's self-defense and would not be turned over to any other country.

The ship was intercepted in the international waters of the Arabian Sea by Spanish forces that were part of an international naval defense line on the lookout for dangerous weapons deliveries in the Persian Gulf region.

``We have no choice but to obey international law,'' White House spokesman Ari Fleischer said. ``What Yemen has done ... does not provide a threat to the United States. We do have ongoing concerns about North Korea's efforts to sell arms around the world.''

Fleischer said the Bush administration will use the incident to strengthen treaties and international agreements dealing with the proliferation of missiles. Bush ordered his nonproliferation experts to begin working on ways to close gaps in international laws that already curb nuclear, biological and chemical sales, administration officials said.

Forces from the amphibious assault ship USS Nassau had been aboard the detained vessel since Tuesday awaiting orders on what to do with it and the weapons, Pentagon officials said.

The incident underscored the challenges Bush faces in the war on terrorism, when the lines dividing allies from potential enemies are often blurred. Yemen is a haven for terrorists, including Osama bin Laden's al-Qaida network, but the government has pledged to help Bush fight terrorism in the Middle East.

``Yemen is doing everything it can to help us on the war on terrorism,'' Fleischer said.

Still, it was clear U.S. officials were disappointed in Yemen's actions. Fleischer was asked why the vessel flew no national flag and why the missiles were hidden aboard the ship. He tersely referred the last question to Yemen.

There was disagreement inside the administration over whether Yemen had broken its word.

A Yemeni official told The Associated Press in San'a that Foreign Minister Abu Bakr al-Kerbi summoned U.S. Ambassador Edmund J. Hull to protest the seizure and ask for the return of the equipment, which was for ``defensive purposes.''

Intelligence officials had tracked the vessel for weeks and the Spanish military stopped it Monday as it sailed 600 miles off the Horn of Africa, without a flag designating its country of origin. The weapons were hidden under a cargo of cement and crew members initially lied about their identity, saying they were Cambodian, officials said.

The seizure came in an interdiction operation that is part of the U.S.-led war on terrorism, officials said, adding that they feared that the weapons were destined for a terrorist state.

The decision to release the missiles came after discussions with Yemeni officials by Powell and Vice President Dick Cheney, Fleischer said.

The Bush administration in August imposed sanctions on the North Korean company Changgwang Sinyong Corp. for selling Scud missile parts to Yemen. At that time, U.S. authorities asked Yemen why it bought the parts, and that country apologized and promised not to do so again, two defense officials said Wednesday.

North Korea was officially silent about the interception but said it had the right to develop weapons to defend itself.

``It is necessary to heighten vigilance against the U.S. strategy for world supremacy and 'anti-terrorism war,''' the North's official newspaper, Rodong Sinmun, said in an editorial. ``All countries are called upon to build self-reliant military power by their own efforts.''

Yemen has been a nominal ally in the global war on terrorism despite strained relations with Washington. Yemen is Osama bin Laden's ancestral homeland, was the site of the bombing of a U.S. warship and has vast lawless areas where al-Qaida members and other terrorists are believed to hide out.

North Korea shocked U.S. officials by admitting in October that it had a secret program to enrich uranium to make nuclear weapons. The Bush administration has vowed to try to solve the problem through diplomacy, though Bush already had named North Korea as part of a three-nation ``axis of evil'' and administration officials have worried that the reclusive Communist dictatorship has become a ``missiles-R-us'' seller to countries such as Iran and Libya.

Crews from the Spanish ships Navarra and Patino stopped the unflagged ship Sosan east of the island of Socotora and called U.S. authorities for assistance, Martinez said. The Spanish navy stopped and boarded the ship after its crew refused to identify themselves.

Yemen's port of Aden was the site of the October 2000 terrorist attack on the USS Cole that killed 17 sailors.


Associated Press reporters Matt Kelley and Ron Fournier contributed to this report.