Seoul: South Korea on Friday demanded the immediate release of two nationals arrested on "groundless" spying charges by North Korea in an incident likely to heighten already elevated cross-border tensions.
North Korea announced late Thursday that it had arrested two South Korean men, identified as Kim Kuk-Gi and Choe Chun-Gil, who had operated as "heinous terrorists" from a base in the Chinese border city of Dandong.
"They zealously took part in an anti-DPRK (anti-North Korea) smear campaign," organised by US intelligence and the South Korean National Intelligence Service (NIS), the North`s official KCNA news agency said.
The two detainees were presented at a "press conference" in Pyongyang, attended by journalists and foreign diplomats.
Reacting to the arrests, the South`s Unification Ministry said both men were being held on "groundless allegations" in violation of international norms.
"The government strongly demands North Korea immediately release our nationals ... and repatriate them at once," ministry spokesman Lim Byeong-Cheol told reporters.
Cross border ties are already strained over ongoing joint South Korea-US military exercises that Pyongyang has condemned as provocative rehearsals for invasion.
The KCNA report said Kim and Choe had gathered information about North Korea`s "party, state and military secrets."
Choe was arrested last December by border guards. It was not immediately clear where or when Kim was taken into custody.
Among other things, Kim was accused of spreading "religious propaganda" from an "underground church" he ran in Dandong, which has a large ethnic Korean community and is a hub of both official and illicit cross-border trade.
Last year, North Korea sentenced a South Korean missionary to hard labour for life on charges of espionage and setting up an underground church.
Although religious freedom is enshrined in the North Korean constitution, it does not exist in practise and religious activity is severely restricted to officially-recognised groups linked to the government.
Pyongyang views foreign missionaries as seditious elements intent on fomenting unrest and those who are caught engaging in any unauthorised activities in the North are subject to immediate arrest.
The charges against Choe included allegations that he recruited a number of North Koreans to gather soil samples from around the North`s main Yongbyon nuclear complex.
"His crimes included acts of destabilising the DPRK and luring the North`s inhabitants to South Korea," KCNA said.