WASHINGTON, Dec. 8, 2010 - U.S. Navy Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, arrived here last night to discuss with Japanese leaders how to better leverage their military expertise and improve defense cooperation in light of North Korean aggression.

Mullen, who flew here after a whirlwind of meetings with South Korean leaders Dec. 8, noted during a news conference yesterday that Japan has a stake in seeing the North Korean threat countered.

“And they have much to offer in terms of viable training opportunities and expertise,” he said. “Having been a Pacific sailor for most of my career, I can attest to their skill and to their earnest desire to contribute to regional security and stability.”

Mullen is slated to meet with Gen. Ryoichi Oriki, Japanese chief of staff, and Defense Minister Toshimi Kitazawa.

The chairman’s visit comes as the United States and Japan conduct the “Keen Sword” bilateral military exercise, which runs through Dec. 10. The exercises include elements throughout mainland Japan, Okinawa and the surrounding waters.

Mullen said yesterday in Seoul that he was encouraged that South Korea had sent military observers to the exercise. He expressed hope it will lead to more trilateral activities involving the United States, Japan and South Korea, as well as more multilateral engagement with other regional partners.

Discussions and engagements like these “illustrate and deepen our relationships,” Mullen said, and cement the countries’ unified position on the North Korean threat.

Mullen also recognized the importance other elements of national power in applying a “whole-of-government” response to the challenge.

He noted the “truly historic” trilateral summit Secretary of State Hillary Rodham Clinton hosted in Washington Dec. 6 in which she, South Korean Foreign Minister Kim Sung-hwan and Japanese Foreign Minister Seiji Maehara discussed the situation.