North Korea disclosed Wednesday that South Korea proposed three inter-Korean summits ― first at Panmunjeom in June, second in Pyongyang in August and third in Seoul in March ― at a secret meeting of officials from the two sides in Beijing on May 9. According to the North’s official media, Pyongyang rejected the offer because Seoul demanded an apology for the atrocities the North committed last year ― the sinking of the Cheonan patrol ship and the shelling on Yeonpyeong Island.

The North’s KCNA also reported, citing a spokesman for the National Defense Commission, that Seoul “begged” for a concession from the North regarding the apology, saying it would be acceptable if the North expresses “regret” instead of an apology.

The South expressed deep regret as to the North’s disclosure of the secret talks, saying Pyongyang distorted its intentions. Seoul officials said the main purpose of the secret meeting was not to propose inter-Korean summits but to demand a “clear and unequivocal” apology from the North for the two cruelties.

It remains to be seen whose account of the story is correct. But regardless of which side is telling the truth, the North’s disclosure itself is deeply troubling. If North Korean leader Kim Jong-il ordered it in his right mind, it means the North will really stop engaging with the South. The North already issued a statement on Monday declaring that it “will never deal with traitor Lee Myung-bak and his clan.”

What motivated the North to take such a hostile stance toward the South? Probably its realization that it can by no means improve ties with the South without making an apology. For Pyongyang, failure to mend fences with Seoul means dashed hopes for a prompt resumption of the six-party talks, since under a three-step formula proposed by China, it is supposed to have meaningful talks with Seoul first before moving to bilateral talks with Washington and multilateral talks with other participants in the six-party process.

Instead of apologizing to the South, the North Korean leader appears to have chosen to revert to his trademark brinkmanship tactic ― heightening tension in the Korean Peninsula and intimidating the South and its allies into offering aid.

Hence it is time for the South raise its guard against possible North Korean armed provocations. The government needs to secure support from China and the U.S. to prevent the North from taking provocative action.