North Korea launched more trash-carrying balloons toward the South after a similar campaign earlier in the week, according to South Korea’s military, in what Pyongyang calls retaliation for activists flying anti-North Korean leaflets across the border.

South Korea’s Defense Ministry did not immediately comment on the number of balloons it had detected or how many have landed in South Korea. The military advised people to beware of falling objects and not to touch objects suspected to be from North Korea, but report them to military or police offices instead.