Four days after North Korea's fifth and possibly most powerful nuclear weapons test, the US Air Force responded with a show of force on Tuesday, flying two powerful, battle-tested B-1 bombers over South Korea. North Korea claimed Friday's test showed it had a nuclear warhead that could be mounted on ballistic missiles, a possibility that increases fears for US allies in the region and also poses a threat to US bases in South Korea, Japan and Guam. "North Korea's nuclear test is a dangerous escalation and poses an unacceptable threat," Gen. Vincent K. Brooks, U.S. Forces Korea commander, said in a statement Tuesday. "The United States has an unshakable commitment to defend allies in the region and will take necessary steps to do so, including operations like this one today." The B-1s were joined by US F-16 and South Korean F-15 fighters in the low-level flyover of Osan Air Base, 40 miles (64 kilometers) south of the South Korean capital of Seoul.
