The Democratic People's Republic of Korea (DPRK) said Friday that it would take decisive action should South Korea aggravate the situation regarding the Kaesong joint industrial zone.

The DPRK's National Defence Commission (NDC) made the warning in a statement carried by the official KCNA new agency, apparently in response to Seoul's formal proposal Thursday for substantive dialogues on the Kaesong issue.

The South Korean side asked Pyongyang to reply by Friday noon, saying that it would have to take important measures if the DPRK refused the offer.

Labeling Seoul's demand as being "little short of an 'ultimatum'", the NDC said the dialogue offer made by South Korea "is nothing but a crafty trick."

If Seoul is worried about the lives of South Koreans still in the industrial zone, it can withdraw all of them to the south side, and Pyongyang will take humanitarian measures to ensure their safety, said the statement.

Should South Korea keep aggravating the situation, it would be the DPRK, not South Korea, "that will be forced to take the final decisive and crucial measure first," the NDC warned.

Later in the day, South Korea's Yonhap News Agency reported that the South Korean unification ministry will announce its official stance on the Kaesong issue at 6 p.m. local time (0900 GMT).

UN Secretary-General Ban Ki-moon on Thursday expressed the hope that operations at Kaesong could return to normal as soon as possible through dialogue.

The UN chief described the industrial zone as a successful example of inter-Korean cooperation, saying the project should not be affected by political and security considerations.