North Korea has warned of retaliatory measures against South Korea that could involve the military, hinting at a possible destruction of the inter-Korean liaison office, which symbolizes reconciliation and economic cooperation between the two Koreas.

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

Describing South Korea as an "enemy," Kim Yo-jong said that North Korea will take its next step against the South as she attacked Seoul over declining bilateral relations and its failure to stop activists from flying anti-Pyongyang leaflets across the border.

Kim said that the right to taking the next action against the "enemy" will be entrusted to the General Staff Department of the North Korean People's Army.

Kim, the first vice director of the Central Committee of the Workers' Party, said that the army will determine something for cooling down the North Korean people’s resentment and surely carry it out.

In addition, Kim said that South Korea will soon witness the "collapse of a useless inter-Korean liaison office."

The unsettling rhetoric comes amid heightened tensions between the two Koreas after North Korea threatened to sever ties and cut off all communication lines with the South last week over leaflet campaigns carried out by North Korean defectors in the South.