A U.S. Air Force cargo jet began on Wednesday to ship helmets and other nonlethal military gear donated by Japan to Ukraine, marking the first time an American aircraft has carried Japanese Self-Defense Forces gear to another country.

A C-17 transport jet flew from the United States to touch down at Yokota Air Base in western Tokyo, and pick up three truckloads of plastic-wrapped boxes. Japan's government declined to list the equipment inside.

"We won U.S. military support to use their planes so we are sending them on those aircraft so the equipment can arrive as soon as possible," said Makoto Oniki, Japan's vice minister of defense.

He spoke at the U.S. military's Asian air transport hub as ground crews behind him loaded the cargo onto the C-17, which can carry about 77 tons.

Japan has followed the United States and other Western industrialized nations in imposing tough sanctions on Russia for its invasion of Ukraine.

It fears the attack, described by Russian President Vladimir Putin as a "special operation," will threaten international norms and could embolden neighboring China to use its military in East Asia.

"Japan's loud voice has made this a global response, because what happens in Ukraine does not stay in Ukraine," the U.S. Ambassador to Japan, Rahm Emanuel, said at the Yokota event.

Emanuel and Oniki were joined by the deputy chief of the Ukrainian Embassy in Tokyo, Oleksandr Semeniuk, who described Russia as being neo-Nazi.

Japan, which renounced the right to wage war after its World War II defeat, follows strict rules that ban weapon exports to conflict zones or countries not subject to United Nations resolutions.