South Korean Acting President and Prime Minister Hwang Kyo-ahn said on Monday that the deployment of the U.S.-made Terminal High Altitude Area Defense (THAAD) battery should happen as soon as possible, arguing the consequences of a nuclear-armed North Korea would be "horrible and beyond imagination."

Hwang presided over a National Security Council (NSC) meeting at South Korea’s Blue House at 0900 KST (1900 EST) a few hours after North Korea test-fired four ballistic missiles at 0736 KST, the Blue House said in a written statement.