WASHINGTON - US Defense Secretary Lloyd Austin said Tuesday that a US soldier crossed the Military Demarcation Line into the Democratic People's Republic of Korea (DPRK) "willfully and without authorization".

"A US National on a JSA (Joint Security Area) orientation tour crossed, without authorization, the Military Demarcation Line into the DPRK," the US-led United Nations Command said Tuesday in a press release.

"We believe he is currently in DPRK custody and are working with our Korean People's Army counterparts to resolve this incident," it added.

The US soldier is identified as Private second class Travis King, aged 23.

Tours to the JSA, a small part of the Demilitarized Zone (DMZ), from South Korea are open to the public. The other DMZ areas are heavily fortified by the two Koreas.

According to US media reports, the US serviceman faced disciplinary measures for assault and was slated to be repatriated to his home country.