A U.S. service member has been detained by North Korea after crossing the border without authorization, the United Nations announced Tuesday.

Here are the latest updates:

U.S. officials work to have Travis King released as North Korea remains silent

Wednesday, July 18

North Korea remained silent Wednesday about the detention of U.S. soldier Travis King, who crossed the border into North Korea, The Associated Press reported.

Meanwhile, the U.S. is working with its North Korean counterparts to have him released, White House press secretary Karine Jean-Pierre said in a press briefing Tuesday.

It is unclear what will happen to King next, but experts have suggested that King, who may have defected, may be used by North Korea for propaganda purposes.

“It’s likely that North Korea will use the soldier for propaganda purposes in the short term and then as a bargaining chip in the mid- to long term,” said Yang Moo-jin, president of the University of North Korean Studies in South Korea, told The Associated Press.

Soldier is identified after crossing border

Tuesday, July 18

The soldier was identified as Pvt. 2nd Class Travis King, U.S. officials told CBS News.

King crossed the Military Demarcation Line between North Korea and South Korea during a tour of the Joint Security Area, the U.N. Command, which oversees the the Demilitarized Zone between the two countries, stated.

“We believe he is currently in DPRK (the Democratic People’s Republic of Korea) custody and are working with our KPA counterparts to resolve this incident,” U.N. Command said in a tweet.

A U.S. official told CBS News that the “troop in question was being escorted back to the United States for disciplinary reasons, but after going through airport security, they somehow returned and managed to join the border tour.”

The Joint Security Area is inside the Demilitarized Zone between the two countries and is open to the public for tours by the U.N. Command, CNN reported. However, tourists are typically kept 20 yards away from the Military Demarcation Line.

A witness who was part of the same tour group told CBS News that they had just visited a building at the site when “this man gives out a loud ‘ha ha ha,’ and just runs in between some buildings.”

The border crossing occurs during a tense time between the U.S. and North Korea due to “North Korea’s barrage of missile tests since the start of last year,” according to The Associated Press. The U.S. also sent a nuclear-armed submarine to South Korea Tuesday, the first time in four decades.

This story will be updated as more information is released.