North Korea has boasted of total success fighting off the coronavirus pandemic and repeatedly denied having any COVID-19 cases within its borders, but the top U.S. military commander in South Korea said on Thursday that those claims are “impossible.”

In a joint interview with CNN and Voice of America (VOA), General Robert Abrams said that based on the intelligence sources he has seen, he is now certain that Pyongyang’s claims of success — which many experts and officials, including Abrams, have already publicly doubted — simply cannot be true.

“I can tell you that is an impossible claim based on all of the intel that we have seen,” Abrams said.

The comments from Abrams are the latest sign that the highest levels of the U.S. government are now convinced that Pyongyang is lying when it says it has no infections at all of the highly contagious virus, which has already killed 50,000 people around the world.

Last week, President Donald Trump said that the DPRK is “going through something” with the virus, but did not elaborate on what that meant.

“If they need help, we’ll give them help,” Trump said at the time. “There’s nobody has what we have, especially with the new tests that are coming out.”

North Korea is known to have one the least-prepared public health systems in the world for dealing with an infectious disease outbreak.

One study last year, conducted by the Johns Hopkins Bloomberg School of Public Health and the nonprofit Nuclear Threat Initiative (NTI), ranked the DPRK last among all nations for “rapid response and mitigation of the spread” of an epidemic.

The country also borders China, South Korea, and Russia, where thousands of infections have been reported.

Rumors of various outbreaks within the North — all unconfirmed — have trickled out of the country for weeks.

At the same time, North Korea does appear to have acknowledged the virus as a real threat.

The country began sealing its borders in late January as the outbreak spread in China. Propaganda outlets told citizens to protect themselves.

Thousands of people were put into mandatory quarantine.

And even Chinese tourists, smuggled goods, and legal trade — all considered crucially important for North Korea’s economy — seem to have been forced to shut down for weeks. North Korea relies on China for more than 90 percent of its trade.

“All members of society should actively participate in tasks to keep the new coronavirus infection from entering our country,” the ruling party’s daily newspaper said in January.

General Abrams also said last month that North Korea had halted its military exercises for “about 30 days” — a sign of how serious Pyongyang was taking the pandemic — although they picked back up in March, when the country conducted more missile tests in a one-month span than it had ever done before.

Despite all of these moves, however — and despite all of the DPRK’s claims of success — the U.S. government still seems wholly unconvinced, even if it doesn’t know for sure how many cases there really are.

They just seem to know that the number is higher than zero.

“We’re not going to reveal our sources and methods. [But] that is untrue,” General Abrams said on Thursday, referring to the DPRK’s claims. “How many, I couldn’t tell you.”