A top South Korean adviser said North Korea’s leader Kim Jong Un is “alive and well.”

"Our government position is firm," Moon Chung-in, the top foreign policy adviser to South Korean President Moon Jae-in, told CNN on Sunday. “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.”

Earlier this week CNN reported that the U.S. is monitoring intelligence that Kim is “in grave danger after a surgery.”

Satellite images of North Korea published Saturday raised more questions about the health of the country’s leader. A train most likely belonging to Kim was visible at his family’s reserved railway station in Wonsan, the Washington-based monitoring project 38 North said in a release.

“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 said.

Speculation around Kim’s health started circulating after he missed one of North Korea’s biggest holidays on April 15, the celebration of his late grandfather Kim II Sung’s birthday.

Kim was last seen in public on April 11.