SEOUL, April 15 -- South Korean President Park Geun- hye on Tuesday apologized for the country's spy agency's evidence forgery to charge a former Seoul municipal government official with espionage.

"Regrettably, wrong practices of the National Intelligence Service (NIS) and holes in the incomplete management system were revealed. I feel sorry for this to cause concern to the people," Park said during a Cabinet meeting.

Her apology was made a day after prosecutors indicted three NIS officials for their alleged involvement in the evidence fabrication.

The prosecution's investigation team said Monday that fake documents were used to charge Yoo Woo-seong, the former Seoul municipal government official, with handing over personal information on more than 200 defectors from the Democratic People' s Republic of Korea (DPRK) to Pyongyang.

After a local court acquitted Yoo of espionage, prosecutors appealed the case and submitted Chinese immigration records on his visit to the DPRK. Some of the documents were found later to have been fabricated.

A deputy NIS chief offered to resign after the announcement, and President Park accepted the resignation.

Park said the intelligence agency must make "bone-grinding" efforts not to repeat this again and turn over a new leaf, noting that if the agency loses trust from the people again with other incidents, it will have to be strongly held accountable.