SEOUL -?The Republic of Korea (ROK) will strike back if it is attacked by the Democratic People's Republic of Korea (DPRK), Defense Minister Kim Kwan-jin said Friday, shortly after the DPRK renewed threats of attacks over anti-Pyongyang propaganda.

"We will completely destroy the source of attack" if the DPRK strikes a border area north of Seoul where anti-DPRK activists are planning to send propaganda leaflets across the border next week, the minister said during a parliamentary audit.

The remark came shortly after the DPRK's military threatened in a statement to carry out a "merciless military strike" on the ROK's territory "the moment a minor movement for the scattering is captured" in the border area.

In the statement carried by the state-owned Korean Central News Agency, the Korean People's Army even advised the residents in the border area to evacuate "in anticipation of possible damage".

DPRK defectors and activists have regularly launched giant balloons containing thousands of propaganda leaflets, which Pyongyang calls "an undisguised psychological warfare".

The threat came a day after the ROK's President Lee Myung-bak paid a surprise visit to a front-line island near the tense maritime border with the DPRK. The DPRK shelled the island two years ago, killing four South Koreans.

"Our goal is not to win a war but to deter provocation," Lee was quoted as saying by Yonhap News Agency. "We have already officially notified the North that we will not tolerate any future provocations."

The two Koreas remain technically at war with each other after their 1950-53 conflict ended with a truce, not a formal peace treaty.