North Korea says it will put military units `` on the highest alert '' It says the units target locations including the Guam mainland , U.S. and Guam . The heightened tensions on the Korean Peninsula came after the North carried out a long-range rocket launch in December and an underground nuclear test last month , prompting the U.N. Security Council to step up sanctions on the secretive regime . The U.S. says it is `` fully capable '' of defending itself and its allies . The Kim Jong Un is angry over Pentagon sanctions and U.S.-South South Korean military exercises .
North Korea says it will put military units `` on the highest alert '' It says the units target locations including the Guam mainland , U.S. and Guam . The U.S. says it is `` fully capable '' of defending itself and its allies . The Kim Jong Un is angry over Pentagon sanctions and U.S.-South South Korean military exercises .