North Korea said the February underground test of a nuclear device was part of a campaign against the United States. The government has threatened to use nuclear weapons against the United States and Tuesday said it was ready to strike U.S. military bases in the region.
The official Korean Central News Agency warned that combat units were ready to strike military bases on "the U.S. mainland and on Hawaii and Guam and other operational zones in the Pacific as well as all the enemy targets in South Korea and its vicinity," China's official Xinhua news agency reports.
North Korea has escalated its rhetoric following U.S.-South Korean joint military drills in the region. The North Korean government has taken a strong stance against the presence of U.S. B-52 bombers deployed over South Korean airspace.
U.S. Defense Secretary Chuck Hagel said this month the United States would position missile defense systems along the U.S. West Coast in response to North Korean aggression.
The Yonhap news agency in South Korea adds the North Korean military has put "all of its field artillery including strategic rocket units and long-range artillery units into the No. 1 combat ready posture."