A group of North Korean defectors has claimed that they sent medical supplies into the North along with banners criticizing Pyongyang for accusing them of transmitting COVID-19 through propaganda leaflets.

According to Fighters for a Free North Korea on Thursday, it released 20 balloons carrying 70-thousand pain reliever tablets, 30-thousand vitamin pills, and 20-thousand masks the previous day.

The balloons also carried a photo of North Korean leader Kim Jong-un and a banner slamming the regime for making the accusation about leaftlets the group had sent earlier.

Citing sources in the North, group chief Park Sang-hak said the virus transmission inside the regime is believed to have started with North Korean workers returning home from China.

The Seoul Metropolitan Police Agency, meanwhile, launched an internal probe into the group's latest claims. Seoul currently bans anti-Pyongyang propaganda activity, citing concerns over the lives and safety of border area residents.

The unification ministry, for its part, urged defector groups to refrain from such activity, saying that they must first consider ways to offer practical assistance to the North Korean people.