North Korea on Sunday floated balloons carrying trash towards South Korea, South Korea’s military said, declaring it would respond with “full-scale” loudspeaker broadcasts.

The South Korean military said the North’s actions raising tensions near the heavily armed border could have fatal consequences, adding the North Korean regime would be solely responsible.

“As we warned several times, the military will carry out loudspeaker broadcasts in full scale and on all fronts starting 1pm today,” the South’s Joint Chiefs of Staff said, calling the North’s launch of balloons vulgar and shameful.

Activists and defectors in South Korea have for years sent their balloons carrying propaganda leaflets and other items into North Korea, angering Pyongyang.

Earlier this week, South Korea’s military decided to resume its round-the-clock loudspeaker broadcast campaign targeting North Korea in response to what it called the despicable launch of balloons by Pyongyang carrying trash across the border.

Since May, North Korea has been floating thousands of balloons with bags of trash attached to them, which have become a new source of tension between the two Koreas.

Blaring propaganda, world news and K-pop music, South Korea’s broadcasts are considered by military officials and activists as an effective form of psychological warfare.