The South Korean government plans to stop people sending balloons with anti-North Korean messages across the border.
The announcement came after Kim Yo-jong – sister of North Korean leader Kim Jong-un – said recent balloon-senders were “human scum.”
For years, activists and defectors have sent messages criticising the North and its leadership across the border.
But the South Korean government said the balloons caused “tension.”
One group told the BBC they had no plans to stop – and had another one million leaflets on order.
In the past, the balloons have also carried dollar notes, and even chocolate.
In 2014, North Korean soldiers attempted to shoot them down – leading to an exchange of fire across the border.
The North has also sent its own leaflets on helium balloons across the border in the past, demanding – among other things – an end to “further hostilities or stupid actions.”