North Korea charged on Friday that any attempt by Seoul to link its leftist lawmaker with Pyongyang would be an "unpardonable provocation" and an insult to Pyongyang's efforts to improve cross-border relations.

Lee Seok-ki, a legislator of South Korea's minor opposition Unified Progressive Party, and three other members of the so-called Revolutionary Organization were arrested on suspicions of conspiring to overthrow the government. The country's spy agency, the National Intelligence Service (NIS), accused them of plotting to blow up key infrastructure and pledging to side with the North in case of a war on the Korean Peninsula. Investigators suggested that Lee and the others may have contacted Pyongyang as part of their activities.

The case was made public while the NIS itself was under investigation on allegations that its agents posted comments on Internet communities during last year's presidential campaign period to influence voters in favor of President Park Geun-hye, the ruling party candidate at the time. 

"What arouses bigger anger is that the puppet south Korean regime is stirring up confrontation with its fellow countrymen in the north, groundlessly pulling up the DPRK over the case," the secretariat of the North's Committee for the Peaceful Reunification of Korea said in a statement.  DPRK stands for North Korea's official name, Democratic People's Republic of Korea. 

"The puppet conservative forces' attempt to deliberately link this case with the north is an intolerable mockery of its efforts for dialogue and peace and will to repair the inter-Korean relations and an unpardonable provocation of them," the statement said.

It was the first reaction out of Pyongyang on the scandal in Seoul. Earlier on Friday, the Chosun Sinbo, a pro-North Korean paper published in Japan, said the scandal was created by the NIS to deflect attention from the controversy over its suspected political activities in last year's presidential race.

In an article titled "The revival of the treason conspiracy law," the Chosun Sinbo blasted the legal actions taken by the NIS as a concerted move to persecute political progressives. The official paper of the General Association of Korean Residents in Japan, picked up in Seoul, also said that actions taken against Lee Seok-ki are a shallow attempt to bail out the NIS from the worst crisis situation in its history.

It said that such hostile actions cannot coexist with better inter-Korean relations. (YONHAP)