Updated

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

Hagel says it's 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.

Speaking with reporters traveling with him to Tokyo, Hagel said such a reaction by nations in the region is, quote, "pretty predictable."

Hagel plans to meet with a number of top leaders in Japan, including Prime Minister Shinzo Abe.