South Korean Defense Minister Jeong Kyeong-doo said on Friday that North Korea is stepping up readiness activities for its air and artillery units, for no apparent reason.

The activity could indicate Pyongyang is preparing another illegal missile test, or it could be related to the disappearance of dictator Kim Jong-un, believed by some outside observers to be dead or incapacitated.

Speaking at a ceremony for commissioned medical and veterinary officers on Friday, Jeong said North Korea “has been heightening military tensions through an unusual increase in the inspection activities for its combat readiness posture, mostly of its artillery, and in its air force planes’ flight operations.”

South Korea’s Yonhap News assumed this activity was related to North Korea’s provocative artillery drills and missile tests:

The latest one took place last week, during which the North fired what appeared to be surface-to-ship cruise missiles off its east coast. On the same day, the North also flew Sukhoi-variant fighter jets and MiG-type planes above the eastern coastal city of Wonsan, and fired multiple air-to-ground missiles into the East Sea. A Joint Chiefs of Staff officer earlier said there has been an increase in North Korea’s surveillance activities in skies near its demarcation line with China over the Yellow Sea, adding that some maritime and air spaces over the body of waters have not been clearly declared either by Pyongyang or Beijing.

This pattern of behavior began too long ago to be interpreted as a sudden tightening of North Korea’s defense posture in response to Kim Jong-un becoming incapacitated, although it is possible the military was generally growing nervous about the corpulent young dictator’s health or about the oncoming coronavirus pandemic. North Korea officially denies having any domestic coronavirus infections to this day, but outsiders give little credit to those denials.

Several South Korean government ministers have stated they do not believe Kim Jong-un is dead or critically ill. One of the few readily available clues to his location is the location of his luxury train, his primary means of travel both within North Korea and internationally.

Watchdog group 38 North reported on Sunday that a train matching the description of Kim’s personal conveyance appeared at the Kim family compound in the coastal resort town of Wonsan sometime between April 15, the first day Kim failed to appear at a major public event, and April 21. Subsequent satellite photos showed the train has been prepared for departure since April 23 but has not left the Wonsan station reserved for the ruling family.

“The train’s presence does not prove the whereabouts of the North Korean leader or indicate anything about his health, but it does lend weight to reports that Kim is staying at an elite area on the country’s eastern coast,” 38 North analysts said.

A top South Korean official on Monday concurred that Kim is staying at the Wonsan report and keeping an unusually low profile at the moment, but insisted he is not critically ill.

“Our government position is firm. Kim Jong-un is alive and well. He has been staying in the Wonsan area since April 13. No suspicious movements have so far been detected,” South Korean President Moon Jae-in’s top foreign policy adviser Moon Chung-in told CNN, which previously reported rumors from the U.S. intelligence community that Kim was “in grave danger after a surgery.”

In another interview on Monday, Moon Chung-in oddly stated that if Kim Jong-un “has a wife like Ri Sol-ju and a younger sister like Kim Yo-jong, he must be sound and reasonable.” This was evidently intended as some obsequious diplomatic flattery of the Kim family, since neither Ri Sol-ju nor Kim Yo-jong is thought to be a medical doctor.

The Washington Post noted on Sunday that rumors had Kim Jong-un undergoing some type of surgical operation on April 12 at the hospital near Mount Myohyang, which is about 150 miles away from Wonsan. It seems unlikely that Kim would have undertaken a train ride of that length to a resort with no major hospital facility if his health was exceptionally frail, and the Post could see no reason why his body would be swiftly relocated to Wonsan if he had died.