North Korea's development of inter-continental ballistic missiles could make it a direct threat to the United States within five years, US Defence Secretary
Robert Gates said Tuesday, DPA reported.
But Gates said he believed North Korea was likely to develop a relatively small arsenal of long-range missiles capable of reaching US territory.
Speaking to reporters after talks with Chinese President Hu Jintao, he said Hu and US President Barack Obama would discuss North Korea during scheduled talks next week.
China and the United States have taken part in stalled six-nation talks aimed at persuading North Korea to end its nuclear weapons programme.
Host nation China has tried without success to persuade North Korea to return to the six-party negotiations, which also involve South Korea, Japan and Russia.
North Korea's shelling of a South Korean island in November has increased tension on the Korean Peninsula.