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 or how many landed in South Korea. South Korea’s Yonhap news agency, citing anonymous military sources, said officials as of Saturday night found about 90 balloons that dropped paper and plastic trash and cigarette buts in areas in the capital, Seoul, and nearby Gyeonggi province.

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. There were no immediate reports of injuries or damage.