Lee Seok-ki, from the small United Progressive Party, was arrested by South Korea's spy agency earlier this month for allegedly discussing launching strikes on national infrastructure with his colleagues in May in the event of a war with North Korea. The National Intelligence Service later handed him over to prosecutors.
Lee has flatly denied the allegation, saying the spy service fabricated the charges to divert criticism that its agents allegedly posted online messages supporting the conservative ruling party candidate and now-President Park Geun-hye and smearing her main liberal rival ahead of December's presidential election.
North Korea angrily reacted to the scandal, calling it a "witch hunt" targeting those espousing greater reconciliation on the Korean Peninsula. North Korea last week cited the rebellion plot as an example of South Korea's confrontational postures that forced it to cancel this week's planned reunions of families separated by the 1950-53 Korean War.
Senior prosecutor Kim Soo-Nam told a news conference today that Lee and his colleagues specifically brought up possible targets to attack, including a telecommunications facility in Seoul, during the May meeting, which drew 130 people. He said the plotters also discussed using websites to find ways to manufacture firearms and bombs.
Kim said Lee believed that high tensions between the two Koreas this past spring would lead to war.