By Dana Priest
Washington Post Staff Writer
Tuesday, August 18, 1998; Page A1

U.S. intelligence analysts believe about 15,000 North Koreans are at work on a vast, secret underground nuclear facility, a development administration officials say may represent a decision by North Korea to abandon a four-year-old agreement to freeze its nuclear weapons program.

Administration officials who have been briefed on the intelligence data, which includes imagery collected by spy satellites, describe a large-scale tunneling and digging operation in a mountainside about 25 miles northeast of Yongbyon, a former nuclear research center where North Korea is said to have produced enough plutonium for two nuclear weapons.

Intelligence analysts believe North Korea is constructing either a nuclear reactor or a reprocessing plant at the site, which they estimate would take two to six years to complete. "There is a volume of activity that certainly suggests that kind of activity," said an administration official briefed on the matter. "We have deep concerns about this."

But U.S. officials gave conflicting accounts of whether the operation violated a 1994 framework agreement between the United States and North Korea in which North Korea pledged to freeze and eventually dismantle its nuclear program in exchange for a U.S. promise of billions of dollars in international aid and help in building two nuclear power plants.

One administration official said the construction violated the agreement. But others said the effort did not technically violate the accord because workers had not, for example, begun pouring cement for the foundation of the facility, something that is explicitly forbidden.

White House spokesman Michael McCurry declined yesterday to comment on the intelligence reports, first reported Monday in the New York Times. He said, "We believe that the [government of North Korea] remains in compliance with the Agreed Framework," as the 1994 accord is called. "We continue to monitor the situation closely."

Nevertheless, on Friday, Charles Kartman, the U.S. special envoy for Korean nuclear issues, is expected to meet with North Korean officials and demand that all construction at the new site be halted, two administration officials said.

The development is likely to add fuel to demands by some Republican leaders that the administration get out of the agreement altogether. Critics have said they do not trust North Korea to uphold its end of the deal and question the administration's handling of its promise to help deliver 500,000 metric tons of fuel oil to the north each year until the first nuclear power plant is on line in 2003 at the earliest.

"If the reports that North Korea has begun construction on a nuclear facility are true," said Rep. Sonny Callahan (R-Ala.), who chairs the Appropriations subcommittee on foreign operations, the framework agreement "should be reevaluated."

"If that is the case, then naturally it's very disturbing," he said. "I would hope the administrative branch would investigate the alleged violation."

Henry Sokolski, executive director of the Nonproliferation Policy Education Center, said: "That the administration was implementing this understanding and publicly asking for money [from Congress for the oil] when they knew this facility existed is outrageous."

Several month ago, the administration began briefing a very small number of congressional members on intelligence reports that some type of large-scale digging had begun at the site, congressional sources said. Several weeks ago, the administration's top national security team briefed select congressional leaders on the intelligence reports. The United States has also briefed South Korea and Japan on the development.

North Korea has insisted it is committed to the agreement but has recently indicated its impatience with delays in lifting economic sanctions and delivering the oil. In the most ominous sign to date, it began maintenance work on the plutonium separation plant it shut down when the agreement was signed.

Korea watchers were nonetheless perplexed over the latest news. If North Korea intended to break the agreement and restart its nuclear program, the leaders of the communist state could simply have restarted existing facilities, said Joel Wit, a Korea expert at the Henry L. Stimson Center.

Wit said the North Koreans could be trying to pressure Washington into lifting the economic sanctions. He said the new construction may also be a way for Korean leader Kim Jong Il to win support from the military. "He may be even more dependent on them than we thought," he said.

The framework agreement was negotiated after North Korea threatened to withdraw from the Nuclear Nonproliferation Treaty, a move that Washington feared signified its intention to speed the development of nuclear weapons and to finance the program by selling nuclear materials and technologies to rogue states.

The pact calls for North Korea to mothball and eventually dismantle its plutonium-producing nuclear reactor and other weapons facilities, and to store its spent nuclear fuel in sealed containers under supervision of the International Atomic Energy Agency.

In return, the United States agreed to arrange for North Korea to acquire two commercial light-water nuclear reactors and to help deliver the fuel oil.