Obama signed the executive order Tuesday, but its existence wasn't disclosed until Wednesday afternoon, more than 15 hours after it went into effect.
The White House said the order was in response to North Korea’s nuclear test on Jan. 6, and its ballistic missile test Feb. 7. The executive order implements sanctions adopted by the United Nations Security Council and Congress, which passed the North Korea Sanctions and Policy Enhancement Act last month.
The North Korean state news agency claimed another breakthrough in missile technology, saying it had developed "heat-resisting materials for rocket with their own efforts and technology after having made painstaking researches of years under the direct guidance of supreme leader Kim Jong Un."
The sanctions also come as the White House also demanded the immediate release of a U.S. college student sentenced to 15 years of hard labor for allegedly taking down a propaganda poster.