Tensions on the Korean Peninsula are high following North Korea’s firing of rockets across the border and South Korea’s subsequent return fire.

North Koreans fired several shells toward loudspeakers broadcasting anti-Pyongyang propaganda and the South retaliated by firing dozens of 155-millimeter howitzer rounds Thursday afternoon. Seoul had resumed propaganda broadcasting after an 11-year hiatus as retaliation against North Korea’s land mines placed on the southern side of the DMZ that injured two South Korean soldiers.

Most of the shells fired by the South and the North on Thursday landed within their respective halves of the DMZ, indicating that both sides were making highly calculated moves.

The North issued an ultimatum threatening military action if the anti-North Korean propaganda loudspeakers are not turned off and dismantled by 5 p.m. on Saturday.

A separate letter from North Korea’s Kim Yang-gon, director of the United Front Department in charge of South Korean affairs, addressed to National Security Adviser Kim Kwan-jin said that North Korea “has the intent” to make efforts to open a channel for improving inter-Korean ties.

On Friday, the South Korean Joint Chiefs of Staff sent a message to its North Korean counterpart promising strong retaliation against any kind of North Korean attack, at the same time warning that the North will have to bear all responsibilities for such retaliatory actions.

The South Korean military declared it would continue broadcasting anti-Pyongyang propaganda materials despite Pyongyang’s ultimatum. In the meantime, South Korea’s military is on top alert and Defense Minister Han Min-koo told an emergency meeting of military commanders Friday morning that North Korea is likely to make provocations after the 5 p.m. deadline.

The South Korean military, which has vowed strong retaliation against North Korean provocations since the attack on South Korean naval vessel Cheonam in March 2010 and the shelling of Yeonpyeongdo Island in November of that year, did exactly that Thursday. The emergency meeting of the National Security Council convened within a few hours of the North Korean shelling reiterated that any future provocations would be dealt with sternly.

In resuming the anti-Pyongyang propaganda broadcasts along the border as retaliation against the land mine incident, the South Korean military jabbed North Korea where it hurt the most. For a country that runs on the cult of the three generation of Kims, any denigration or criticism of its leader is a capital offense.

North Koreans are reported to be preparing for an offensive and as Defense Minister Han said, another North Korean military action may be likely in the days to come. In sending messages of war and offer of a possibility of a way out of the situation, North Koreans are up to their usual antics — trying to foment discord among South Koreans. While the government and the military should act in a measured but resolute manner against any threats or provocations by the North, Koreans should also remain calm and unified in standing up against North Korean provocations.