(ATTN: UPDATES throughout)
SEOUL, July 18 (Yonhap) -- A U.S. citizen has crossed the military demarcation line separating the two Koreas into North Korea without authorization, the U.S.-led U.N. Command (UNC) said Tuesday.
The man moved into the North during a tour to the Joint Security Area in the Demilitarized Zone (DMZ) and is believed to be in North Korea's custody, according to the UNC.
The command did not elaborate on other details.
"We ... are working with our KPA counterparts to resolve this incident," the UNC said in a tweet referring to the North's Korean People's Army.
The incident came as Pyongyang is expected to respond angrily to the first U.S. nuclear-capable ballistic missile submarine visit to South Korea in decades and the inaugural session of the allies' Nuclear Consultative Group in Seoul this week.
Some observers raised the possibility that the incident could lead to direct engagement between Washington and Pyongyang on the release of the U.S. national and other bilateral issues.
The UNC oversees activities in the DMZ.
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