North Korea has said that it will stop sending balloons carrying garbage across the border with South Korea, but vowed to restart the practice if activists from the South resume flying anti-regime leaflets.

North Korean Vice Minister of Defense Kim Kang Il said in a statement carried by state-run media that Pyongyang had sent more than 3,500 balloons carrying 15 tons of waste over the border from Tuesday through Sunday.

Kim said late Sunday that the “unpleasant” measures had given the South Korean side a taste of “how much effort is needed” to clean up the waste, saying that Pyongyang would be “temporarily” halting its actions.