Secretary of State Mike Pompeo said Wednesday he has no information on North Korean leader Kim Jong Un's health, but added the United States will push for Pyongyang's denuclearization regardless of any change in leadership.

Kim has stayed out of public sight for about two weeks, fueling speculation about the state of his health and increasing concern as to what would happen with the nuclear-armed country in the case of the sudden demise of the third-generation hereditary leader.

"I don't have anything to add to the status of Chairman Kim," Pompeo said at a press conference at the State Department.

But noting that he had met Kim Jong Un's sister Kim Yo Jong, who is drawing attention as a possible successor, during past trips, Pompeo said, "Our mission is the same regardless of what transpires inside of North Korea with respect to their leadership...And that's the fully verified denuclearization of North Korea."

In an interview with Fox News the same day, Pompeo said that the United States is "watching closely" what is going on in North Korea, not only in regard to the country's leader but also on such matters as the new coronavirus and the possibility of a famine.

U.S. Secretary of State Mike Pompeo 

"We're watching each of those things closely, as they have a real impact on our mission set, which is to ultimately denuclearize North Korea," he said.

The U.S.-based website 38 North, which monitors North Korea, said commercial satellite imagery from Wednesday showed a train at a station in the coastal city of Wonsan that is reserved for the exclusive use of the Kim family.

A train was observed at the same station on April 21 and again on Thursday. The website said it cannot be determined whether the train has remained at the station since then, but it does not appear to be prepared for departure.

It also said it cannot tell whether it is Kim Jong Un's train or whether he was on it when it arrived, but that the presence of the train lends "weight to the multiple reports that Kim has been staying in the Wonsan area."

North Korean leader Kim Jong Un [KCNA/Kyodo]

April 12 was the most recent date at which a public appearance by Kim Jong Un was reported by state-run media. The Korean Central News Agency said he had presided over a meeting of the Political Bureau of the Central Committee of the ruling Workers' Party of Korea, held the day before.

He missed the celebration of the birth of his late grandfather and the nation's founder, Kim Il Sung, on April 15, one of the most important holidays in the country.

U.S. President Donald Trump, who has boasted about his "good relationship" with Kim Jong Un after meeting him three times, denied last week a U.S. media report that said Washington was monitoring intelligence about Kim being in grave danger after surgery.

At the first-ever U.S.-North Korea summit in June 2018 in Singapore, Trump promised to provide security guarantees to Pyongyang in return for "complete" denuclearization of the Korean Peninsula.

But talks have since brought little progress, with the two countries at odds over issues such as the level of sanctions relief that should be extended to Pyongyang in return for denuclearization steps. In the meantime, North Korea has continued testing weapons.