North Korea has threatened that a balloon launch of anti-Pyongyang leaflets scheduled for Saturday will be a declaration of war.

Unusually, the proposed balloon launch is also coming under fire from other defector groups and politicians within the South Korean conservative camp.

The group planning the launch, the Citizens’ Alliance for Sending North Korean Leaflets (CASNL), has promised to send 100,000 leaflets into North Korea on Saturday, October 25.

The group, which is headed by Busan University Professor Chae Uwon, could not be reached for comment.

CASNL’s plan has outraged progressive politicians and residents living near the planned launch site,