The nation's intelligence chief reportedly said on Monday that he believes the late Former President Roh Moo-hyun made remarks to the effect of giving up the western sea border during the 2007 summit with late North Korean leader Kim Jong-il, a ruling party lawmaker said.

Nam Jae-joon, the chief of the National Intelligence Service (NIS), made the remarks as a witness before a parliamentary investigative committee, said Rep. Kwon Seong-dong of the Sanuri Party after attending a closed-door investigation session at the National Assembly.

The investigative committee is looking into allegations that the NIS meddled in last year's presidential election in favor of the ruling party. 

Nam's presence marks the first time that a spy chief has stood as a witness at the Assembly.

"(President Roh) sympathized with (North Korean leader) Kim Jong-il's remarks of, 'Let's abolish the Northern Limit Line (NLL)' during the summit, which I deem as abandonment," Nam was quoted as saying.

The NLL is an inter-Korean maritime border in the West Sea, and the scene of several bloody inter-Korean skirmishes. The communist country has never recognized the border, demanding the line be redrawn farther south. 

Nam also denied rumors that the disclosure of the 2007 summit transcripts in Late June by the NIS was made through communications with the presidential office Cheong Wa Dae, according to the lawmaker. 

"The public disclosure was made thoroughly on (our) independent judgment," Nam was quoted as saying.

On suspicions over the spy agency's intervention in the December presidential election via online comments, Nam insisted that the alleged smear campaign against then opposition presidential candidate Moon Jae-in was in fact part of the agency's psychological warfare campaign against North Korea.

In his disclosed opening remarks earlier in the day, Nam apologized to the public for "causing concern" over the scandal and promised to regain the people's trust by re-examining his agency's past practices over the course of the parliamentary probe.

The scandal centers on allegations that former NIS chief Won Sei-hoon ordered an online smear campaign to sway public opinion in favor of the ruling party ahead of December's presidential election.

In June, prosecutors indicted Won and then Seoul police chief Kim Yong-pan on charges of illegally intervening in the election.

Nam also asked the ruling and opposition party lawmakers on the investigative committee to help dispel "misunderstandings" about his spy agency's anti-North Korea psychological warfare.

"The NIS did its best to fulfill its mission of protecting the national interest amid rapidly changing conditions, but we were not able to inform the public in detail for confidentiality and other reasons, and at times, aroused suspicions," Nam said.

The committee received the spy agency's report and questioned the spy chief behind closed doors, citing the sensitivity of the issue.

Opposition parties have called on President Park Geun-hye to dismiss Nam over the scandal and also over his decision in June to declassify and disclose a transcript of the 2007 inter-Korean summit. (Yonhap News)