(CNN) -- A South Korean left-wing activist was arrested Thursday for an unauthorized visit to North Korea, a South Korean national police official said. Roh Su-hui, a leader with an organization close to North Korea, was taken into custody as he crossed back into South Korea after three months, the official said. Roh visited Pyongyang to commemorate the 100th day since the death of the country's late leader, Kim Jong Il, according to KCNA, North Korea's official news agency. KCNA called his visit "a righteous deed in view of traditional beautiful manners" and urged the South not to arrest him.
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Roh Su-hui went to North Korea to mark the 100-day anniversary of Kim Jong Il's death
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He is likely to be charged under the National Security Law, a police official said
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Tensions remain high between the two countries
@placeholder did not send any representatives to the North after Kim's death.