Against the backdrop of Russia's takeover of Ukraine's Crimean region, Defense Secretary Chuck Hagel said on Saturday that a key message he will deliver to leaders in Tokyo this weekend is that the US is strongly committed to protecting Japan's security.

Hagel said it was understandable for nations to be concerned as they watch the events unfold in Ukraine, where Russian troops are still massed along the border. The issue reverberates in Asia where China, Japan and other nations are locked in bitter territorial disputes, including over disputed islands in the East China Sea.

"It's a pretty predictable, I think, reaction, not just of nations of this area and this region but all over the world," Hagel told reporters traveling with him to Tokyo. "I think anytime you have a nation, Russia in this case, try to impose its will to refine and define international boundaries and violate the territorial integrity and sovereignty of a nation by force, all of the world takes note of that."

Assistant secretary of state Daniel Russel also said this week that Russia's annexation of Crimea heightened concern, particularly among some Southeast Asian nations, about the possibility of China "threatening force or other forms of coercion to advance their territorial interests”.

While the US has repeatedly said it takes no side on the question of the disputed islands' sovereignty, it recognises Japan's administration of them and has responsibilities to protect Japanese territory under a mutual defence treaty.

Hagel said the US wants the countries in the region to resolve the disputes peacefully. But he added that the United States would honor its treaty commitments.

There is no "weakness on the part of the United States as to our complete and absolute commitment to the security of Japan," Hagel said. "So I don't think there is any indication or any evidence that we're doing anything but strengthening our commitment to the security of Japan."

Asked whether the inability of the US and its international partners to stop Russia might give Asian nations reason for worry, he said the allied response for Ukraine has been significant. And while he said there is no military solution to the problem, the diplomatic and economic sanctions imposed on Russia have isolated that nation and "there will be consequences for that".

Speaking to more than 150 US and Japanese troops gathered in a hanger at the base, Hagel noted that this is his fourth trip to the region all part of an effort to make sure that everyone understands that America is a friend and partner and reinforce "our continued commitment to our partnerships, our friendships and our treaty obligations".

Hagel's trip to Japan comes at the close of a three-day meeting in Hawaii with defence ministers from Southeast Asian nations. He will later travel to China, where he said he looks forward to talks about expanding military cooperation as well as the chance to air differences on the disputes.

Hagel said he would encourage Chinese leaders to abide by the international code of conduct.

China has expressed displeasure about recent moves by the US to provide additional military assets and support to Japan.

Last October, the US and Japan agreed to broad plans to expand their defense alliance, including plans to position a second early warning radar there by the end of this year. There is already one in northern Japan and the second one would be designed to provide better missile defense coverage in the event of a North Korean attack.

The US will also begin sending long-range Global Hawk surveillance drones to Japan this month for rotational deployments, and they are intended to help step up surveillance around the Senkaku islands, a source of heated debate between Japan and China which both claim the remote territories.

In its latest symbolic gesture of support for Japan, the US decided not to send a warship to participate in a Chinese naval parade as part of the Western Pacific Naval Symposium because the Japanese were not invited. However, US military leaders, including the navy's top officer, Admiral Jonathan Greenert, will attend the symposium and view the ship review.

Hagel plans to meet with a number of top leaders in Japan, including Prime Minister Shinzo Abe, Defense Minister Itsunori Onodera and Foreign Minister Fumio Kishida.

The US trade representative, Michael Froman, will travel to Japan on Monday for high-level talks, his office said on Saturday. Talks about a 12-nation Pacific Rim trade pact have been bogged down as the US trieS to persuade Japan to lower trade barriers.



Acting deputy US trade representative Wendy Cutler had already been scheduled to visit Tokyo next week, as bilateral talks have accelerated ahead of a visit to Japan later this month by President Barack Obama.