North Koreans, guided by their leader Kim Jong Un, held artillery exercises apparently targeting South Korean islands, UPI quoted the North's news agency as saying Thursday. Although the Korean Central News Agency did not say when the exercises were held, South Korea's Yonhap News Agency said they were likely conducted Wednesday and involved batteries capable of targeting Baengnyeong and Yeonpyeong islands in the Yellow Sea. Yonhap, quoting the KCNA, said Kim oversaw live ammunition drills to test the capabilities of artillery batteries under real battle conditions. Yonhap said the Baengnyeong and Yeonpyeong islands just south of the Northern Limit Line act as the de facto sea border between the two Koreas, although the North does not recognize the NLL. The artillery exercises come as North Korea, under Kim, has stepped up its highly provocative threats against the United States and South Korea to express its anger against the recent U.N. Security Council resolution that severely tightened existing sanctions for the North's Feb. 12 nuclear test and its earlier long-range missile test. The North's latest action comes as the United States and South Korea are holding their annual military exercises. The North also has scrapped the Korean Armistice that halted the 1950-53 Korean War.