North Korea's nuclear weapons and ballistic missiles pose a serious threat to the United States, the U.S.' top spy said Wednesday.

"North Korea's nuclear weapons and missile programs also pose a serious threat, both regionally and beyond," National Intelligence Director James Clapper told a Senate Select Committee on Intelligence hearing. "Although both Taepodong-2 launches ended in failure, the 2009 flight demonstrated a more complete performance than the July 2006 launch."  

Were it turned into an international continental ballistic missile, the Taepodong-2 could reach at least part of U.S. territory, and there is a risk that the rocket or related technologies are exported, Clapper said. On Jan. 11, Defense Secretary Robert Gates predicted that Pyongyang will have ICBMs that can attack Alaska or the western coast of the U.S.

Yet in the wake of the 2009 launch, Vice Chairman of the Joint Chiefs of Staff James Cartwright downplayed the risk of proliferation, asking who would buy ICBMs from a country that has failed three times in a row and that has never succeeded in a test?

The evaluation was apparently changed because North Korea late last year completed a big missile test site in Tongchang-ri, North Pyongan Province.