The United States special envoy on North Korea Stephen Bosworth says the U.S. is hoping for a diplomatic solution to the threats posed by Pyongyang.

He told a Senate hearing on Friday that the Obama administration's strong preference is to engage in "serious and effective diplomacy."

He said Washington is willing to sit down with Pyongyang if the communist country agrees to return to the six-party nuclear talks.

Bosworth also said that although denuclearization of the Korean Peninsula is the key goal, talks with North Korea, if resumed, should go beyond the nuclear issue and include such concerns as the normalization of relations.

But the envoy added that if the North does not respond to dialogue, the U.S. and its allies in the region will need to take the necessary steps to assure security in the face of a growing threat.