( CNN ) -- Amid talk of a possible nuclear bomb test , North Korea vowed Tuesday to carry out a `` high-intensity , all-out action . '' The promise emerged from a meeting of the ruling Workers ' Party and was reported by the state-run news agency KCNA . `` It emphasized the necessity to continue on with launching artificial satellites ... and long-range rockets , '' the agency reported . It also said that the party leadership promised to `` stage a high-intensity , all-out action , and maximize its preparation ... so that just after an order is issued , we can destroy and sweep America and the South Korean puppet army , and achieve the historic achievement of reunified Korea . '' Last month , the U.N. Security Council voted to tighten sanctions on Pyongyang , after the North launched a satellite aboard a long-range rocket in December . The North Koreans responded by announcing they planned another nuclear test and more long-range rocket launches as part of a new phase of confrontation with the United States . Since then , U.S. officials have told CNN they believe a nuclear test could come at any time . `` I do n't think there 's anything special to it , except that it comes in context of renewed trash-talking from Pyongyang . But on whole it 's part and parcel of their threats to engage in more provocations , '' a senior U.S. administration official said about Tuesday 's announcement . North Korea has conducted two previous nuclear tests , in 2006 and 2009 , and proclaimed itself a `` nuclear state '' in 2012 . U.S. analysts believe the 2006 test had a yield of about 1 kiloton -- comparable to the explosive power of about 1,000 tons of TNT -- while the second was roughly 2 kilotons , National Intelligence Director James Clapper told a Senate committee in 2012 . By comparison , the bomb the United States dropped on Hiroshima in 1945 was roughly 15 kilotons . CNN 's Elise Labott and Matt Smith contributed to this report .
NEW : ` ` It 's part and parcel of their threats to engage in more provocations , '' says U.S. official . The Pentagon has been warning for months that North Korea is preparing a missile attack on the United States or its allies - but it was unclear if Pyongyang had actually tested such an attack. North Korea has conducted two previous nuclear tests , in 2006 and 2009 .