President Barack Obama says he will insist that the self-proclaimed mastermind of the Sept. 11 attacks will be subject to "the most exacting demands of justice."

Speaking at a news conference in Tokyo with Japan's Prime Minister Yukio Hatoyama, Obama would not comment directly on the decision to send Khalid Sheikh Mohammed (HAH'-leed shayk moh-HAH'-med) and four other Guantanamo Bay detainees to federal court in New York for trial, saying he did not want to pre-empt Attorney General Eric Holder's announcement, expected later Friday morning.

But when asked whether he could assure the American public that it would be safe to try the suspects on U.S. soil, Obama said the move was both a prosecutorial and a national security decision.