When Prime Minister Shinzo Abe addresses Japan's wartime past in a statement marking the 70th anniversary of the end of World War II, the reaction of ally Washington will likely be as much, if not more, on his mind than that of Asian nations that suffered from Japanese military aggression.

U.S. officials have welcomed Abe's push to strengthen the alliance and give Japan a bigger global security role less constrained by its pacifist Constitution. But they have also made clear they are loath to see Abe stir regional tensions with comments that critics could construe as whitewashing history.

Abe, whose conservative agenda includes a less apologetic stance over Japan's wartime past, has previously expressed reservations about earlier apologies. They include a 1995 landmark statement by then-Prime Minister Tomiichi Murayama and 1993 remarks by then-Chief Cabinet Secretary Yohei Kono over "comfort women" who were forced to work in Japan's wartime military brothels.