North Korea has threatened to blow up balloons carrying DVDs of "The Interview" and propaganda leaflets.
Pyongyang's warning comes a week after the chief of a Seoul-based activist group said 10,000 copies of the film and 500,000 leaflets would be airdropped in North Korea.
Park Sang-hak, the activist behind the campaign, said the airdrop would be carried out on or around 26 March to mark the fifth anniversary of the sinking of the South Korean vessel Cheonan.
North Korea has been incensed by the satirical film that mocks its leader Kim Jong-un. It revolves around a fictional CIA plot to assassinate Kim.
"All the firepower strike means of the frontline units of the [Korean People's Army] will launch without prior warning..... to blow up balloons," the North's army said in a warning, according to the state-run mouthpiece Korean Central News Agency (KNCA).
The statement added that the campaign "deliberately [escalates] tension on the Korean Peninsula where the situation has reached the brink of war", referring to the recent joint military drills conducted by US and South Korean forces.
The North advised South Koreans living near the border areas to evacuate.
South Korea said it would retaliate if the North opens fire first. On previous occasions, the North attempted to shoot down propaganda balloons prompting brief armed encounters with South Korean forces.