President Donald Trump might want to check in with North Korea on that denuclearization thing: US intelligence agencies believe North Korea has been upping production of fuel for nuclear weapons, according to a new report by NBC News.

Even as Pyongyang engaged in diplomatic talks with the US in the lead-up to President Trump’s summit with North Korean leader Kim Jong Un in Singapore earlier this month, North Korea was increasing production of enriched uranium for nuclear weapons, NBC’s Courtney Cube, Ken Dilanian and Carol Lee reported Friday night.

North Korea has stopped missile and nuclear tests, but there is no evidence they’re decreasing stockpiles or have stopped production, one official told NBC News, and multiple officials said they believe that North Korea is trying to deceive the US, essentially extracting concessions from America without giving anything up. This isn’t the first time Pyongyang has promised to freeze or end its nuclear program, and in the past, those pledges have all gone unrealized.

NBC spoke with more than a dozen American officials for the report.

Separately, 38 North, a site that tracks North Korea, captured satellite images last week showing that North Korea is improving infrastructure at one of its nuclear research facilities, the Yongbyon Nuclear Scientific Research Center. 38 North clarifies that work doesn’t necessarily have anything to do with the country’s denuclearization plan — the world should expect Pyongyang’s nuclear program to “proceed with business as usual” until official orders come down from Kim.

Beyond Yongbyon and other known sites, US officials have long thought that North Korea has at least one undeclared facility to enrich nuclear fuel. It may not be the only one. According to NBC News, recent US intelligence concludes there is more than one secret site.

Trump took a big victory lap on North Korea. It was almost definitely too soon.

It appears that North Korea is trying to get as much as it can out of Trump — who has already offered major concessions, including canceling joint US-South Korean exercises on the Korean peninsula — while at the same time keeping its nuclear activities going. Bruce Klinger, a former CIA analyst and North Korea expert at the Heritage Foundation, told NBC that the “observed activity,” including improvements at Yongbyon, “appears inconsistent with a North Korean intent to abandon its nuclear weapons programs.”

Since the June 12 summit, Trump has repeatedly bragged about his accomplishments on North Korea. After arriving back in the US, the president declared that there is “no longer a Nuclear Threat from North Korea” in a tweet.

Just landed - a long trip, but everybody can now feel much safer than the day I took office. There is no longer a Nuclear Threat from North Korea. Meeting with Kim Jong Un was an interesting and very positive experience. North Korea has great potential for the future! — Donald J. Trump (@realDonaldTrump) June 13, 2018

At a rally in Duluth, Minnesota last week, Trump defended his decision to meet with Kim and said the dictator had promised, in the first sentence of their deal, “a total denuclearization of North Korea.”

That’s not true. Beyond reports suggesting that North Korea isn’t ramping down its nuclear weapons efforts, Kim never agreed to a total denuclearization of North Korea. As Vox’s Alex Ward pointed out, Kim agreed to “work toward complete denuclearization of the Korean Peninsula.” In other words, North Korea will give up its weapons as soon as the US — which protects South Korea under its “nuclear umbrella” — withdraws military support from South Korea.

Secretary of State Mike Pompeo admitted in an interview with CNN just this week that the outlines of the deal are a lot fuzzier than the president stated, saying that there’s no timeline for North Korea to take action on the denuclearization front. “I am not going to put a timeline on it, whether that’s two months, six months, we are committed to moving forward in an expeditious moment to see if we can achieve what both leaders set out to do,” Pompeo said.

And Trump’s administration still views North Korea as an “unusual and extraordinary threat,” at least according to the letter they sent Congress renewing longstanding sanctions on the country.