South Korea on Monday expressed deep regrets over the Democratic People's Republic of Korea (DPRK)'s refusal to Seoul's invitation to a regional security conference set to be held in September.

South Korea's Defense Ministry Friday invited the DPRK to the Seoul Defense Dialogue, a vice ministerial-level regional security forum launched in 2012 by Seoul. This year's forum is slated for three days from September 9.

The DPRK's Committee for the Peaceful Reunification of the Fatherland said in a statement, carried Sunday by the state-run KCNA news agency, that the South Korea was seeking to make a political use of the dialogue offer.

It said atmosphere should be formed first for any inter-Korean dialogue.

South Korea's National Assembly Speaker Chung Ui-hwa offered last week to the DPRK's counterpart holding talks at any convenient date and site for the DPRK side, but the DPRK committee rejected the proposal.

"It was very regrettable (for the DPRK) to refuse our dialogue offer by the speaker and our invitation to the Seoul Defense Dialogue," Seoul's Unification Ministry spokesman Jeong Joon-hee told a regular press briefing.

Jeong urged the DPRK to respond positively to South Korea's repeated dialogue offers, saying that there has been no change in Seoul's position of improving relations with Pyongyang through dialogue and cooperation.