North Korea has threatened to scrap its military tension reduction agreement with South Korea, taking issue with anti-Pyongyang propaganda leaflets sent into the North. 

North Korean leader Kim Jong-un's powerful sister Kim Yo-jong issued the warning in a statement carried by the North's official Korean Central News Agency on Thursday.

Kim Yo-jong said that South Korea must be well aware of the 2018 Panmunjeom Declaration and the 2019 inter-Korean military accord, in which the two Koreas agreed to ban all hostile acts, including flying anti-Pyongyang propaganda leaflets across the border. 

Kim said that if South Korean authorities fail to take proper steps for the senseless act, they will be forced to pay a dear price. 

She warned that if Seoul lets the situation go on, it will have to prepare for the possibility of a complete withdrawal of the already desolate Gaesong Industrial Park, shutdown of the inter-Korean joint liaison office, or the scrapping of the inter-Korean military agreement.