The balloons carried toilet paper, batteries and suspected poo into two border provinces.

Photographs shared on social media show bags attached via string to white translucent balloons carrying toilet paper, dark soil, and batteries, among other contents.

Police and military officers are seen in some of these photographs.

South Korea’s Yonhap news agency reported that “some of the fallen balloons carried what appears to be faeces judging from its dark colour and odour”.

South Korea’s military condemned the act as a “clear violation of international law”.