US President Barack Obama said in an interview aired Tuesday that he did not believe North Korea could yet arm a missile with a nuclear warhead, but predicted new provocations from Pyongyang.

Obama also said he hoped that the isolated state, which has rattled Asia with a string of provocative actions and bellicose rhetoric, would eventually stand down and use diplomacy to address its perceived grievances.

The president was asked in the interview with NBC's Today Show whether Pyongyang currently had the capability to arm a ballistic missile with a nuclear bomb.

"Based on our current intelligence assessments we do not think they have that capacity," Obama said in the interview recorded on Monday.

"But we have to make sure that we are dealing with every contingency out there and that's why I've repositioned missile defense systems to guard against any miscalculation on their part."

A US lawmaker last week quoted a report from the military's Defense Intelligence Agency saying Pyongyang may have succeeded in the technologically difficult task of making a nuclear weapon small enough to fit on a warhead.

But the Pentagon and the White House poured cold water on the assessment.

The United States and its Asian allies remain on alert for a possible new missile test from the Stalinist state.

"I think all of us would anticipate that North Korea will probably make more provocative moves over the next several weeks," Obama said.

But he added that he hoped to be able to "contain" Pyongyang's provocations and that it would be possible to move to a phase "in which they try to work through diplomatically some of these issues."

US Secretary of State John Kerry just returned from a trip to Asia, where he raised the prospect of talks for North Korea, but stressed it would have first have to demonstrate it was prepared to stand down its nuclear program.