Officials say Pvt. 2nd Class Travis King has been a calvary scout with the U.S. Army since January 2021.

The 23-year-old had been stationed in South Korea, but had recently been held in a prison there on charges of assault, the AP reported. While it is unclear how long he'd been incarcerated, according to CBS News, King was released to U.S. officials at the military hub in the country about a week ago.

Before bolting into North Korea, King was being escorted to an airport outside of Seoul where he was expected to board a plane bound for Fort Bliss, Texas, to face military disciplinary action.

Officials got him through airport security, but somehow King managed to ditch the escort and make his way out of the terminal and back to the Demilitarized Zone between North and South Korea. That is where officials said King, who was dressed in civilian clothes, joined a tour of the Korean border village of Panmunjom.

One member of the tour group described the incident on a now-deleted Facebook post, saying the King cried out, then ran between two buildings and eventually into North Korea. It is unclear if he planned to defect.

Where is Travis King now?

During a Tuesday press conference, Defense Secretary Lloyd Austin said officials believe King is in the custody of the Democratic People's Republic of Korea.

"I'm absolutely foremost concerned about the welfare of our troop," Austin said.

So far, there has been no official word from North Korea.

King's mother, Claudine Gates who lives in Racine, Wis., told ABC News that she was shocked when Army officials told her on Tuesday that her son had fled.

"I can't see Travis doing anything like that," Gates said.

She added that the last time she heard from her son was a few days ago when he called to tell her he was headed back to his base in Fort Bliss, according to the outlet.

"I'm so proud of him. I just want him to come home, come back to America," Gates said.

Meanwhile, it is still unclear whether King planned his escape into North Korea or whether it was something he did on a whim. Some experts say that the trip just to the Demilitarized Zone takes days of planning.

Jacco Zwetsloot, the host of the North Korea News podcast and a former employee of a tour company that took U.S. soldiers to the border, told the BBC that there was "no way this person could escape from the airport one day and book on to one of these tours the next."

He told the outlet that these trips usually take three days to plan and tour-goers must submit their passports and other credentials to authorities.

Can U.S. officials bring King home?

The soldier's detention poses a fresh diplomatic challenge for Washington's wary relationship with North Korea; the U.S. does not have formal diplomatic relations with Pyongyang.

NPR's Greg Myre said North Korean leader Kim Jong Un may endeavor to leverage the incident for political gain.

"It certainly wouldn't be surprising if North Korea tries to score some propaganda points or makes demands in exchange for handing over the soldier," Myre told All Things Considered.

Many U.S. citizens have been detained by North Korea over the years.

The last time was in 2018 when Bruce Byron Lowrance​ illegally entered the country from China. Lowrance was held in custody for a month before his release.

Before that, Tony Kim, a Korean-American professor, and Kim Hack Song, a former South Korean politician who also held U.S. citizenship, were both detained in 2017 and then released over a year later. Their release came on the same day as another American Kim Dong Chul, who had been held since 2015. The three were set free during a visit North Korea by then Secretary of State Mike Pompeo and ahead of the much anticipated summit between then-President Donald Trump and Kim Jong Un in Singapore later that year.

One of the more high-profile detainments was that of Otto Warmbier in 2016, a U.S. college student who was on a tour of the country before he was detained. Warmbier was accused of taking a poster from his hotel and held for more than a year. He was eventually released to U.S. officials while he was in a coma and then died just days after returning to the U.S.

NPR's Emily Olson contributed to this story. [Copyright 2023 NPR]