White House senior adviser Dan Pfeiffer urged North Korea to end its bellicose rhetoric and provocative action. He stopped short of describing what response, if any, the US would take if the regime launched a strike. We ve seen the reports about North Korea moving missiles in. We wouldn t be surprised if they did a test, Pfeiffer said today on ABC s This Week program. \"This is absolutely a situation of concern, he added. He declined to talk about hypotheticals and what the US response would be to a missile launch. North Korea needs to stop its actions, Pfeiffer said. North Korea\'s leader Kim Jong-un regime warned last week that the moment of explosion is approaching soon and said it s poised to conduct a smaller, lighter and diversified nuclear strike. Kim s regime has moved a missile to its eastern coast rocket launch site, possibly for test-firing, according to South Korea s defense minister. North Korea was seen loading two mid- range missiles onto mobile launchers and hiding them in a facility near the east coast, Yonhap reported April 5, citing unidentified South Korean military sources. North Korea in the past has sought to mask its intentions and deceive surveillance tools by steps such as displaying dummy missiles and covering test sites.