美国有线新闻 CNN 美国副总统彭斯在三八线发警告 对朝战略忍耐时代已结束（在线收听）

We're back to our daily coverage of explaining international events today. It starts with an American leader's visit to a place that's still technically at war.

No peace treaty has ever been signed on the Korean peninsula, though an armistice formally stopped the fighting and the conflict in 1953. The U.S. fought in the war. It's now an ally of South Korea. Yesterday, U.S. Vice President Mike Pence visited the demilitarized zone, the DMZ, the border line that divides North and South Korea.

Standing less than 100 feet from North Korean soldiers, the vice president said the Trump administration would have a different approach to North Korea than previous administrations did.

MIKE PENCE, VICE PRESIDENT OF THE UNITED STATES: They're going to abandon the failed policy of strategic patience, but we're going to redouble our efforts to bring diplomatic and economic pressure to bear on North Korea. Our hope is that we can resolve this issue peaceably.

AZUZ: To do that, the U.S. is relying heavily in North Korea's main ally, China, to pressure North Korea to give up its controversial nuclear program.

So far, the North has indicated it won't. And though it tried out a missile on Sunday, the weapon apparently blew up right after it launched.

U.S. officials don't think it was a long range missile that could reach other continents, but South Korea has said that if the North tests one of those, or tests a nuclear weapon again, the North would receive a powerful punishment.