"The North Koreans have to understand that what they're doing is very dangerous," Hagel said. "I don't think we're doing anything extraordinary or provocative or out of the ... orbit of what nations do to protect their own interests." The U.S., he added, must make it clear to South Korea, Japan and other allies in the region that "these provocations by the North are taken by us very seriously, and we'll respond to that."
U.S. Forces Korea announced in a statement Thursday that two B-2 stealth bombers flew from an air base in the U.S. and dropped dummy munitions on a South Korean island range before returning home. The Pentagon said this was the first time dummy munitions had been dropped over South Korea, but late Thursday it was unclear whether there ever had been any B-2 flights there.
The joint drills are likely to heighten the escalating tensions between the U.S. and North Korea in recent weeks, including Pyongyang's threat to carry out nuclear strikes on Washington and Seoul. North Korea also is angry at new U.N. sanctions over its latest nuclear test last month.
Asked if the U.S. has seen North Korea take any actual threatening military steps in response to the bombers, Dempsey said the North has moved some artillery units across the demilitarized zone from Seoul and some maritime units along the coasts. But so far, he said, "We haven't seen anything that would cause us to believe they are movements other than consistent with historic patterns and training exercises."
The military drills are only the latest U.S. response to what officials see as a growing North Korean threat. The Pentagon is also planning to strengthen its defenses against a potential North Korean missile attack on the U.S.