South Korea flew around 400,000 anti-Pyongyang propaganda leaflets across the inter-Korean border, local media reported on Friday, citing a government source.

The move, a sign of resumption of psychological campaign against the Democratic People's Republic of Korea (DPRK), came after an artillery skirmish between the two sides in waters off the west coast of the divided Korean Peninsula Tuesday, which claimed at least four South Koreans lives, including two civilians.

The leaflets, which denounced the DPRK regime, called for more openness in the neighboring country and promoted the superiority of democracy, were sent from four locations in Gangwon and Gyeonggi Provinces south of the border via balloons late Tuesday, according to Seoul's Yonhap News Agency.

The South Korea's military printed near 1.2 million propaganda leaflets after Seoul accused Pyongyang of sinking a South Korean warship in March that killed 46 sailors, but it had held off on flying them north.

Seoul also set up the loudspeakers along the heavily fortified border with the North, as part of countermeasures following the ship sinking.

A senior official said the military has not been decided yet whether to resume anti-North propaganda broadcasting, and "it will depend on North's further move," according to local media.

Meanwhile, Pyongyang warned Seoul last month to stop anti-DPRK psychological operations, saying that if South Korea did not halt the broadcasting and the scattering of leaflets, it would "never be able to escape the KPA's (Korean People's Army) physical strikes" at the sources of the propaganda.

According to an agreement reached by the north and south in June 2004, both sides were to stop all the propaganda campaigns, including loudspeaker broadcasting and slogans from Aug. 15 of that year.