President Park Geun-hye apologized Tuesday for the spy agency's alleged forgery of evidence used in charging a North Korean defector with espionage, ordering the embattled agency to make thorough efforts to reform itself.

Park issued the apology during a Cabinet meeting, a day after prosecutors indicted two officials of the National Intelligence Service for their alleged roles in the scandal. NIS Director Nam Jae-joon also offered an apology earlier in the day.

The swift apology shows Park takes the issue seriously, aides said. The move was also seen as reflecting concern that the scandal, if mishandled, could hurt the ruling Saenuri Party's chances in June's nationwide local elections.

It was the fourth time Park has apologized since taking office last year. 

"Regrettably, wrong practices of the NIS and holes in its management system have been revealed. I feel sorry for causing concern to the people," Park said. "The NIS must make excruciating efforts to overhaul itself to make sure this kind of incident won't repeat itself. Should there occur any case of it losing people's trust again, I will take strong measures to hold it accountable."

The scandal began following revelations that fake documents were used in the case of Yoo Woo-seong, a former official of the Seoul municipal government charged with handing over personal information of more than 200 North Korean defectors to Pyongyang.

After a local court acquitted Yoo of espionage, prosecutors appealed the verdict and submitted Chinese immigration records on Yoo's visits to the North. But some of the documents were later found to have been forged, and suspicions have since arisen that the spy agency was involved in the alleged fabrication.

On Monday, prosecutors announced the results of a two-month investigation into the scandal, including the indictment of the two NIS officials. But prosecutors said they found no evidence that higher-ranking officials, including Nam, were involved.

A deputy NIS chief immediately offered to quit, and Park accepted the resignation.

Still, the announcement touched off strong criticism that the investigation was designed to give impunity to the spy agency chief. Opposition parties have long demanded Nam's resignation, holding him responsible for the evidence forgery and other scandals involving the agency. (Yonhap)