WASHINGTON, April 13: The United States said on Tuesday that the information it had received from scientist Dr A.Q. Khan had enabled it to expose North Korea's claims that it did not have a nuclear weapons programme.

"We would note that Mr Khan has admitted to assisting North Korea's enrichment programme, and his admissions have put the lie to North Korea's denials," the state department's spokesman Richard Boucher told a briefing.

The spokesman, however, said he could not comment on a report published in the New York Times on Tuesday that Dr Khan had visited an underground nuclear weapons site in North Korea.

"As far as specific visits and information about Mr Khan, I think that would have to come from him or the Pakistani government. There are things about US intelligence in there that, again, I can't get into," he said.

Mr Boucher said US authorities were working very closely with Pakistan to "dismantle the A.Q. Khan network. That's been our primary goal, as Secretary Powell stated during his visit there... been working very hard with them to do that." Asked if the US was getting everything it wanted from Dr Khan, the spokesman said: "I don't think I can quite make that judgment at this point."