South Korea ? North Korea vowed today to launch an all-out attack against South Korean loudspeakers and other propaganda facilities along their heavily fortified border, warning it can even turn Seoul into a “sea of flame.”

In 2004, the rival Koreas ended decades of propaganda campaigns as relations warmed following a landmark summit in 2000. However, South Korea resumed radio broadcasts to the North last month and installed a dozen propaganda loudspeakers along the border.

The resumption of psychological warfare was part of punitive steps taken against the North over the deadly sinking of a South Korean warship.

South Korean Defense Minister Kim Tae-young told a parliamentary hearing Friday that loudspeaker broadcasts would begin after the U.N. Security Council decides on any new measures against the North, Yonhap news agency reported.