"The United States pointedly showed off its military prowess over the Pacific and the Korean Peninsula on Sunday in response to North Korea’s launch Friday of a missile capable of reaching the U.S. mainland, a test Pyongyang said was a “stern warning” for Washington to back off from threats and more sanctions. In a sign that tensions are spiraling upward rapidly, the United States flew two supersonic B-1 bombers over the Korean Peninsula as part of a joint exercise with Japan and South Korea. And U.S. forces conducted a successful missile defense test over the Pacific Ocean, sending aloft from Alaska a medium-range ballistic missile that it detected, tracked and intercepted using the Terminal High Altitude Area Defense System."