US president Barack Obama on Thursday called on North Korea to end its "belligerent approach," as the Pentagon backed away from an intelligence report which suggested North Korea might have developed nuclear weapons which could be fit onto a ballistic missile.
Pentagon spokesman George Little 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 intelligence report.
The statement came after a lawmaker read out the findings of a Defense Intelligence Agency (DIA) report at a congressional hearing earlier Thursday that appeared to signal a shift in Washington's view of North Korea's nuclear
The DIA assessment said US analysts had "moderate confidence the North currently has nuclear weapons capable of delivery by ballistic missiles" but that the reliability of the weapons was "low."
The intelligence report marked the first time the US government had suggested North Korea may have succeeded in a years-long quest to miniaturize a nuclear device so that it could be placed on a missile.
Defense secretary Chuck Hagel and the US military's top officer, General Martin Dempsey, appeared caught off-guard when the report's findings were disclosed at a hearing of the House Armed Services Committee.
Follow coverage of escalating threats in Northeast Asia
After the hearing, administration officials scrambled to explain what appeared to be a change in the government's portrayal of the North Korean threat.
A senior US official, who spoke on condition of anonymity, told the AFP news agency that the administration had not changed its evaluation that Pyongyang was still not at a point where it could deliver a nuclear warhead on a ballistic missile.
"The North Koreans have never demonstrated this capability and we don't believe they are able to now," the official said.
The confusion over the report came against the backdrop of mounting tensions on the Korean peninsula, with Pyongyang issuing bellicose threats and preparing to possibly launch medium-range missiles.
The Pentagon, which has bolstered missile defenses around the Korean peninsula, said it was closely watching North Korea amid speculation the regime would fire conventional missiles in the run-up to national celebrations on April 15th.
"The United States continues to closely monitor the North Korean nuclear program and calls upon North Korea to honor its international obligations," Little said.
Obama addressed the tensions after a meeting with UN secretary general Ban Ki-moon in the Oval Office. He said that "nobody wants to see a conflict" with the North, but that the United States is ready to take necessary measures to defend itself.
"We both agree that now is the time for North Korea to end the kind of belligerent approach that they've been taking," Obama said.
"It's important for North Korea, like every other country in the world, to observe basic rules and norms."
While the US president emphasized that Washington would "continue to try to work to resolve some of those issues diplomatically," he made it clear that the United States would be ready to face any eventuality and defend its allies.
"The United States will take all necessary steps to protect its people and meet our obligations under our alliances in the region," Obama said.
Ban, who is from South Korea, said he was "deeply concerned... by the continuing tensions on the Korean peninsula" and hailed what he called Washington's "measured response" to the litany of threats issued by Pyongyang.
"We hope that border countries including China, who may have influence on North Korea, can exercise their leadership and influence so that this situation will be resolved peacefully," the UN chief said.
Earlier Thursday, G-8 foreign ministers including US Secretary of State John Kerry strongly condemned Pyongyang over its nuclear program, warning it would face further sanctions in the event of a missile launch.