No one knows if Kim Jong Un is “brain dead,” “gravely ill,” or just recuperating from surgery at his family’s summer retreat in Wonsan.

Now the U.S. appears to be trying to get some more information by flying surveillance planes over the secretive kingdom.

Since Monday, when reports first claimed that Kim was struggling to recover from heart surgery conducted on April 12, the U.S. Air Force has conducted multiple flights over the Korean Peninsula every day.

The U.S. surveillance flights were first spotted by the aviation tracking Twitter account Aircraft Spots, which tracked the flights as they passed over Seoul.

These flights are not unusual for the U.S. Air Force, but what is unusual is that the flights have been tracked.

Experts told the South Korean news agency Yonhap that it might have let some of them be spotted ”intentionally,” to pressure the North into revealing what is going on in the country.

The U.S. surveillance flights ramped up earlier this month following a North Korean missile test on April 14. Kim typically oversees such tests, but state media has yet to publish any official images or a report on the launch.

On Wednesday, U.S. President Donald Trump said the U.S. was as much in the dark as everyone else when it comes to Kim’s current health status.

He said that although there were “very serious medical reports, nobody has confirmed” them so far.

“These are reports that came out and we don't know," Trump added. "I just have to say to Kim Jong Un, good luck. I've had a very good relationship with him. I can only say this, I wish him well.”

The reports that Kim had undergone surgery and was struggling to recover first emerged in a website run by North Korean defectors. U.S. media, citing U.S. intelligence sources then claimed Kim was “gravely ill” and “brain dead” — though they subsequently walked back much of that reporting.

South Korean intelligence sources have dismissed the reports, saying there is no evidence of unusual activity in North Korea. Chinese intelligence sources speaking to Reuters agreed with this assessment.

On Thursday, South Korea’s Channel A TV station ran a story, citing U.S. intelligence sources, saying that Kim was in the coastal city of Wonsan and had traveled there last week after several people close to him had contracted the coronavirus.

North Korea is one of the only countries on the planet to report no official cases of coronavirus — though experts are highly skeptical of this claim.

Cover: People watch a TV screen showing a news program reporting about North Korean leader Kim Jong Un with a file image at the Seoul Railway Station in Seoul, South Korea, Tuesday, April 21, 2020. (AP Photo/Lee Jin-man)