Against the backdrop of Russia’s takeover of Ukraine’s Crimean region, U.S. Defense Secretary Chuck Hagel said Saturday he will convey to Japanese leaders that the U.S. is strongly committed to protecting their country’s security.

Hagel said it is understandable that countries are concerned by the unfolding events in Ukraine, where Russian troops remain massed along the border. The issue reverberates in Asia where China, Japan and others are in bitter territorial disputes, including over disputed islands in the East China Sea.