North Korea has detained a U.S. soldier from Wisconsin for crossing its borders without authorization.

After 23-year-old Travis King was released from a South Korean prison, he made his way to North Korea.

Here is what is known about King and the situation so far.

Who is private Travis King?

U.S. Army Pvt. 2nd Class Travis King is a 23-year-old cavalry scout with the 1st Armored Division. USA Today reported that King joined the Army in January 2021.

King graduated from Park High School in Racine in 2020, and has family who live in Racine, including his mother.

King's maternal grandfather, Carl Gates, said his grandson joined the Army because he "wanted to do better for himself," and he was drawn to service because he has a brother who is a police officer and a cousin in the Navy, the Milwaukee Journal Sentinel reported.

What happened to Travis King before he was detained in North Korea?

Prior to entering North Korea, King served a 47-day sentence in a South Korean prison for assault after he allegedly kicked and damaged a South Korean squad car.

King was released on July 10 and was due to be sent home to Fort Bliss, Texas. There, he could have faced additional military discipline and discharge from the service.

King’s stint in prison was not the first time he faced legal trouble in South Korea.

In February, a court fined him 5 million won ($3,950) after he was convicted of assaulting an unidentified person and damaging a police vehicle in Seoul last October, according to a transcript of the verdict obtained by The Associated Press.

The ruling said King had also been accused of punching a 23-year-old man at a Seoul nightclub, though the court dismissed that charge because the victim didn’t want King to be punished.

How did Travis King get into North Korea?

Upon his release from prison, King was escorted as far as customs but left the airport before boarding his plane. Instead, the following day, King joined a tour in the border village of Panmunjom, inside the heavily fortified Demilitarized Zone, which separates North and South Korea.

During the tour, King was seen running across the border. One woman who was on the tour with King said she initially thought this was some kind of stunt — and that she and others in the group couldn’t believe what happened.

According to USA Today, King was last seen entering a van and being whisked away by officials from North Korea, U.S. officials said.

It's not clear how King spent the hours before joining the Panmunjom tour. The Army released his name and limited information after King’s family was notified.

What is the U.S. government saying about Travis King's detention in North Korea?

United Nations Command said Tuesday that King was in North Korean custody and it was working to "resolve the incident," USA Today reported.

White House press secretary Karine Jean-Pierre said the U.S. government was working with its North Korean counterparts to "resolve this incident."

North Korea has not acknowledged or commented on the situation.

What is Travis King's family saying about his detention in North Korea?

Army Col. Isaac Taylor said Tuesday that a U.S. service member "willfully and without authorization" crossed into North Korea. However, King's mother, Claudine Gates, told ABC News she couldn't see her son intentionally entering North Korean territory.

On Wednesday, Claudine Gates made a plea for King's safe return from her porch in Racine.

King's grandfather, Carl Gates, said he hoped his grandson could come home and receive help.

Are people allowed to leave North Korea?

North Korea is one of the most heavily restricted countries in the world. In October, the U.S. Department of State reissued a Level 4 travel advisory, telling U.S. citizens not to travel to North Korea.

The Department of State warns: "Do not travel to North Korea due to the continuing serious risk of arrest and long-term detention of U.S. nationals. Exercise increased caution to North Korea due to the critical threat of wrongful detention."

According to the organization Human Rights Watch, North Korea's authoritarian regime maintains tight control over the country's citizens "through threats of execution, imprisonment, enforced disappearances, and forced hard labor in detention and prison camps."

The border between North and South Korea is one of the most heavily fortified in the world. It runs for about 150 miles and divides the Korean Peninsula roughly in half along the "38th parallel" — the cease-fire line of demarcation between the two nations that has existed since the end of the Korean War in 1953, USA Today reported.

However, Bruce Klingner, a former CIA deputy division chief for South Korea, told USA Today that it is relatively easy to cross from South Korea into North Korea via the so-called Joint Security Area of the Demilitarized Zone ― which is where King crossed ― because there's no formal barrier, and the border consists of a line of raised concrete blocks.

Hundreds of North Koreans attempt to flee to South Korea each year, where they seek better economic opportunities and an escape from political oppression and famine. But cases of defections across the demilitarized zone are extremely rare ― and even rarer for Americans and South Koreans going the other way, USA Today reported.

Have other Americans been held captive in North Korea?

Yes, but King is the first American known to have been held in North Korea in almost five years.

In recent years, some American civilians have been arrested in North Korea on allegations of espionage, subversion and other anti-state acts, but were released after the U.S. sent high-profile missions to secure their freedom.

In May 2018, North Korea released three American detainees who returned to the United States on a plane with then-Secretary of State Mike Pompeo during a short period of warm relations. Later in 2018, North Korea said it expelled American Bruce Byron Lowrance. Since his deportation, there have been no reports of other Americans detained in North Korea before Tuesday.

Those releases stood in striking contrast to the fate of Otto Warmbier, an American college student who died in 2017, days after he was released by North Korea in a coma following 17 months in captivity. His parents said he had been tortured and suffered brain damage.

Will Travis King be released from North Korea?

King's detention comes at a time of elevated animosity between the U.S. and North Korea. On July 19, North Korea test-fired two ballistic missiles into the sea in an apparent protest of the deployment of a U.S. nuclear-armed submarine in South Korea for the first time in decades.

Tae Yongho, a former minister at the North Korean Embassy in London, said North Korea is likely pleased to have "an opportunity to get the U.S. to lose its face" after the submarine arrived in South Korea.

Tae, now a South Korean lawmaker, said North Korea was unlikely to return King easily because he is a soldier from a nation technically at war with North Korea, and he voluntarily went to the North.

USA Today and Journal Sentinel reporters Bill Glauber and Drake Bentley contributed to this report.