SEOUL, South Korea – The U.S. special envoy for North Korea said Monday that Pyongyang’s claim that it has a new uranium enrichment facility is provocative and disappointing but not a crisis or a surprise.

Stephen Bosworth’s comments, following a meeting with South Korean Foreign Minister Kim Sung-hwan, came as the United States and the North’s neighbors scrambled to deal with Pyongyang’s revelation to a visiting American nuclear scientist of a sophisticated enrichment operation.

“This is obviously a disappointing announcement. It is also another in a series of provocative moves” by North Korea, Bosworth said. “That being said, this is not a crisis. We are not surprised by this. We have been watching and analyzing the (North’s) aspirations to produce enriched uranium for some time.”

Kim also played down the facility, telling reporters: “It’s nothing new.”

Top U.S. military officials, however, warned that the facility could speed up the North’s ability to make and deliver viable nuclear weapons.

U.S. Defense Secretary Robert Gates said it could enable North Korea to build “a number” of nuclear devices beyond the handful it is presumed to have already assembled. Gates was speaking in Bolivia, where he is attending a regional defense conference.

The American scientist, Siegfried Hecker, said in a weekend report that he was taken during a recent trip to a small, industrial-scale uranium enrichment facility in North Korea.

Hecker, a former director of the U.S. Los Alamos Nuclear Laboratory who is regularly given rare glimpses of the North’s secretive nuclear program, said the North Korean program had been built in secret and with remarkable speed.

It wasn’t immediately clear why the North chose to reveal the facility. It could be a ploy to win concessions in nuclear talks or an attempt to bolster leader Kim Jong Il’s apparent heir. It’s also possible the North is serious about producing nuclear electricity.

The Obama administration has shunned direct negotiations with North Korea following its nuclear and missile tests last year and in the wake of an international finding that a North Korean torpedo sank a South Korean warship in March, killing 46 sailors.

North Korea told Hecker it began construction on the centrifuge facility in April 2009 and finished only a few days before the scientist’s Nov. 12 visit. The facility appeared to be primarily for civilian nuclear power, Hecker said. But, he said, it “could be readily converted to produce highly enriched uranium bomb fuel.”