In concluding with "moderate confidence" that North Korea could make a small enough weapon, the assessment by the Defense Intelligence Agency warned the weapon's "reliability will be low," The New York Times reported Thursday.
The assessment was disclosed Thursday by Rep. Doug Lamborn, R-Colo., during a budget hearing of the House Armed Services Committee with Defense Secretary Chuck Hagel and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff.
James R. Clapper, director of national intelligence, said in a statement later Thursday the assessment did not represent a consensus of the U.S. intelligence community and "North Korea has not yet demonstrated the full range of capabilities necessary for a nuclear armed missile."
Pentagon press secretary George Little also issued a statement trying to qualify the assessment's conclusion, the Times said.
"It would be inaccurate to suggest that the North Korean regime has fully tested, developed or demonstrated the kinds of nuclear capabilities referenced in the passage," Little said.
North Korea has taken a number of provocative actions -- including nullifying the armistice agreements ending the Korean War, severing the military hotline and shuttering the Kaesong Industrial Complex -- after it was condemned and sanctioned for its nuclear test in February.
On Wednesday, a South Korean minister said a mid-range ballistic missile has been moved to North Korea's east coast and could be launched "any time."
A spokesman for the South Korean Defense Ministry, Kim Min-seok, said Friday his country doubted "North Korea has reached the stage of miniaturization."
The report was issued last month. Its executive summary said the Defense Intelligence Agency "assesses with moderate confidence the North currently has nuclear weapons capable of delivery by ballistic missiles; however, the reliability will be low," the Times said.
A spokeswoman for Lamborn said the material he cited during the hearing was unclassified. Pentagon officials said the report was classified but the one-paragraph finding had been declassified but not released.