North Korean missile
FILE PHOTO: A North Korean long-range rocket is launched into the air at the Sohae rocket launch site, North Korea, in this photo released by KyodoREUTERS/Kyodo/File Photo

U.S. intelligence agencies believe North Korea has increased production of fuel for nuclear weapons at multiple secret sites in recent months and may try to hide these while seeking concessions in nuclear talks with the United States, NBC News quoted U.S. officials as say.

NBC quoted five unidentified U.S. officials as saying that in recent months North Korea had stepped up production of enriched uranium for nuclear weapons, even as it engaged in diplomacy with the United States in a report on Friday.

The network cited U.S. officials as saying that the intelligence assessment concludes that North Korea has more than one secret nuclear site in addition to its known nuclear fuel production facility at Yongbyon. "There is absolutely unequivocal evidence that they are trying to deceive the U.S.," NBC quoted one official as saying.

The CIA declined to comment on the NBC report. The State Department said it could not confirm it and did not comment on matters of intelligence. The White House did not respond to a request for comment.

The NBC report raises further questions about North Korea's readiness to enter serious negotiations about giving up a weapons program that now threatens the United States, in spite of Trump's enthusiastic portrayal of the summit outcome.

Donald Trump Kim Jong Un
Donald Trump shows the document, that he and North Korea's leader Kim Jong Un signed acknowledging the progress of the talks and pledge to keep momentum goingReuters

North Korea agreed at the summit to work toward denuclearization of the Korean Peninsula, but the joint statement signed by Kim and Trump gave no details on how or when Pyongyang might surrender its nuclear weapons.

Ahead of the summit, North Korea rejected unilaterally abandoning an arsenal it has called an essential deterrent against U.S. aggression. U.S. Secretary of State Mike Pompeo said last week he would likely go back to North Korea before long to try to flesh out commitments made at the Trump-Kim meeting.

Trump said last week North Korea was blowing up four of its big test sites and that a process of total denuclearization has already started, but officials said there had been no such evidence since the summit.

This week, Washington-based North Korean monitoring project 38 North said recent satellite imagery showed North Korea had made rapid improvements to facilities at Yongbyon since May 6, but it could not say if such work had continued after June 12.

[ Source- Reuters]