Kim Yo Jong, sister of North Korean leader Kim Jong Un, on Tuesday called South Korea’s joint military exercises with the U.S, calling the drills “an act of betrayal” and vowed to strengthen her country’s “preemptive strike capabilities.” “The combined exercises are the most inventive expression of the U.S. hostile policy toward the DPRK,” Kim said in a statement through the state Korean Central News Agency, adding that the exercises were rehearsals for a possible invasion in the north, threatening all North Koreans. “In order to cope with the ever-growing U.S. military threats, we will further strengthen absolute deterrence, namely national defense power aimed at responding quickly to any military act against us as well as preemptive strike capabilities,” she said.

Kim called for the U.S. to “pull back” its armed forces deployed in South Korea. About 28,000 U.S. troops are in the country to keep the peace between the nations, but Kim said peace on the Korean Peninsula will never “take root” if the U.S. remains in the south.