North Korea threatened to attack US bases in Japan and on Guam Thursday in reaction to flights by US B-52 bombers in South Korea during joint manoeuvres, while the Stalinist state also activated air raid alerts. The North Korean army's command accused the United States of preparing for a nuclear war in its ongoing exercises with the South Korean military. "The US should not forget that the Andersen base [on the US territory of Guam] ... as well as naval bases at Japan's main island and Okinawa, are all within the range of our precision target assets," the military said in statement run by the Korean Central News Agency. Tensions have been high on the peninsula recently as North Korea carried out its third nuclear test in February and issued threats against South Korea and the United States.