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 saying.

In a report on Friday, the network said what it described as the latest U.S. intelligence assessment appeared to go counter to sentiments expressed by President Donald Trump, who tweeted after an unprecedented June 12 summit with North Korean leader Kim Jong Un that “there is no longer a nuclear threat from North Korea.”

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.

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 programme that now threatens the United States, in spite of Trump’s enthusiastic portrayal of the summit outcome.