North Korea says it's investigating Travis King in 1st response to United Nations messages

North Korea for the first time responded to messages regarding U.S. Army Private 2nd Class Travis King, who ran across the demilitarized zone two weeks ago, according to defense officials.

"I can confirm that the [Democratic People's Republic of Korea] has responded to United Nations Command, but I don't have any substantial progress to read out," Pentagon press secretary Brig. Gen. Pat Ryder said during a briefing Tuesday when asked by ABC News for an update on attempts to communicate with North Korea.

The message, which came on Monday Eastern time, was superficial -- the North Koreans merely acknowledging that King had crossed into the country, and saying that the incident is under investigation.

King, 23, has been a cavalry scout in the U.S. Army since 2021 and had no previous deployments before serving in South Korea, according to Army spokesperson Bryce Dubee. King spent 47 days in a South Korean jail after an altercation with locals, and was released in June according to U.S. officials.

After about a week on a U.S. base completing out-processing tasks, King was escorted to South Korea's Incheon International Airport where he was to board a flight and end up in Fort Bliss, Texas, where he most likely faced separation from the Army, officials told ABC News. The escort walked with King as far into the airport as possible without having tickets, parting with him at the customs or security checkpoint.

Instead of boarding his flight, King at some point left the airport, joining a tour of the demilitarized zone, or DMZ, the heavily-fortified area separating North Korea from South Korea. King broke from the group, then "willfully and without authorization crossed the military demarcation line," Defense Secretary Lloyd Austin said two days after the July 18 incident.

On the North Korean side, King was driven away in a van, and is believed to have been taken to the capital city, Pyongyang.

"I'm absolutely foremost concerned about the welfare of our troop. We will remain focused on this, and this will develop in the next several days," Austin added.

U.S. officials say they remain concerned for King and have no knowledge of his wellbeing.