WASHINGTON — North Korea probably has advanced its nuclear knowhow to the point where it could arm a ballistic missile with a nuclear warhead, but the weapon wouldn’t be very reliable, the Defense Intelligence Agency has concluded.
North Korean leader Kim Jong Un has rattled much of Asia with threats to launch a nuclear strike, although top U.S. intelligence officials said Thursday they believe Kim is using those threats to win concessions on foreign aid rather than trying to start a war.
President Barack Obama warned North Korea to end its belligerence after discussing the threats with U.N. Secretary General Ban Ki-moon in the Oval Office.
‘‘We both agree that now is the time for North Korea to end the belligerent approach they have taken and to try to lower temperatures,’’ Obama told reporters. ‘‘Nobody wants to see a conflict on the Korean Peninsula.’’
But, he said, ‘‘the United States will take all necessary steps to protect its people.’’
The North on Thursday delivered a fresh round of war rhetoric with claims it has ‘‘powerful striking means’’ on standby. The statement was the latest in a torrent of warlike threats seen by outsiders as an effort to scare and pressure South Korea and the U.S. into changing their North Korea policies, and to show the North Korean people that their young leader is strong enough to stand up to powerful foes.
Secretary of State John Kerry was headed Thursday to East Asia, where he planned talks with officials in Seoul, Beijing and Tokyo about North Korea.
The DIA assessment was revealed Thursday at a public hearing by Rep. Doug Lamborn, R-Colo., who said it was an unclassified segment of a classified DIA report on North Korea’s secret nuclear weapons program. The DIA conclusion was confirmed by a senior congressional aide who spoke on condition of anonymity because the Pentagon had not officially released the contents. The aide said the report had been produced in March.
‘‘DIA assesses with moderate confidence the North currently has nuclear weapons capable of delivery by ballistic missiles. However, the reliability will be low,’’ the report said, according to Lamborn, who read it aloud.
Notably absent from that unclassified segment of the report was any reference to what DIA believes is the range of a missile North Korea could arm with a nuclear warhead. Much of its missile arsenal is capable of reaching South Korea and Japan, but Kim has threatened to attack the United States as well.
At the House Armed Services Committee hearing in which he revealed the DIA assessment, Lamborn asked Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, whether he agreed with it. Dempsey said he had not seen the report.
‘‘You said it’s not publicly released, so I choose not to comment on it,’’ Dempsey said.
The DIA assessment is not out of line with comments Dempsey made Wednesday when he was asked at a Pentagon news conference whether North Korea was capable of mating a nuclear warhead to a ballistic missile that could reach Japan or beyond.
In response, Dempsey said the extent of North Korean progress on designing a nuclear weapon small enough to operate as a missile warhead was a classified matter. But he did not rule out that the North has achieved the capability revealed in the DIA report.
‘‘They have conducted two nuclear tests,’’ Dempsey told a Pentagon news conference. ‘‘They have conducted several successful ballistic missile launches. And in the absence of concrete evidence to the contrary, we have to assume the worst case, and that’s why we’re postured as we are today.’’ He was referring to recent moves by the U.S. to increase its missile defense capabilities in the Pacific.
At the House hearing where Lamborn revealed the DIA conclusion, Defense Secretary Chuck Hagel was asked a different version of the same question: Does North Korea have the capability to strike U.S. territory with a nuclear weapon? Hagel said the answer is no.
‘‘Now does that mean that they won’t have it or they can’t have it or they’re not working on it?’’ Hagel added. ‘‘No. That’s why this is a very dangerous situation.’’
At a separate hearing Thursday, U.S. officials offered their assessment of the North Korean leader, who is a grandson of the country’s founder, Kim Il Sung.
Director of National Intelligence James Clapper told the House Intelligence Committee that he thinks Kim, who took control after his father, Kim Jong Il, died in 2011, is trying to show the U.S., the world and his own people that he is ‘‘firmly in control in North Korea,’’ while attempting to maneuver the international community into concessions in future negotiations.
‘‘I don’t think ... he has much of an endgame other than to somehow elicit recognition’’ and to turn the nuclear threat into ‘‘negotiation and to accommodation and presumably for aid,’’ Clapper said.
Clapper said the intelligence community believes the North would use nuclear weapons only to preserve the Kim regime, but that analysts do not know how the regime defines that.