South Korean politicians have condemned the psychological warfare conducted by the National Intelligence Service (NIS) in the 2012 presidential race that was aimed at manipulating voters in an attempt to secure now-impeached Park Geun-hye’s victory.

Axar.az reports citing on RT news that, on Thursday, an internal probe of the South Korean spy agency revealed that from 2009 to 2012, the NIS instructed 30 teams to bombard social media with messages to help shape public opinion in the run-up to the 2012 presidential election.

The probe accuses former NIS chief Won Sei-hoon of organizing the smear campaign involving anti-North Korea psychological warfare units to influence the 2012 election in favor of Park Geun-hye, who ended up winning. The teams also engaged in a campaign to criticize rival candidate Moon Jae-in.

“The teams were charged with spreading pro-government opinions and suppressing anti-government views, branding them as pro-North Korean forces’ attempts to disturb state affairs,” the internal NIS probe revealed, as quoted by Financial Times.

It is alleged that the campaign hired civilians and used as many as 3,500 social media accounts to support the conservative party.

A spokesman for former President Park, who is now standing trial on corruption and abuse of power charges after being impeached, claimed that the NIS inquiry launched in June is politically motivated.

“The NIS says it will dissociate itself from politics but it is meddling in politics again by starting this probe,” Kang Hyo-sang of Park’s opposition Liberty Korea Party said in a statement.

Political parties across the spectrum have criticized the spy agency’s election meddling.

“Though it is just the tip of the iceberg, it is very shocking,” Kim Hyun, a spokesman for the ruling Democratic Party, told reporters, as cited by Yonhap. “Those involved in the case must come forward and tell the truth.”

“It is clearly the NIS’ unlawful political intervention,” Kim Yoo-jung from the center-left People’s Party said. “(Those responsible) should pay the price for unpardonable illicit acts.”

Park won the 2012 election with 51.6 percent of the vote to Moon Jae-in’s 48 percent.