Naoto Kan, secretary general of the Democratic Party of Japan, stressed on Wednesday the need for a U.S. military presence in Japan, distancing himself from DPJ President Yukio Hatoyama's call for an alliance without the stationing of U.S. forces in the country.

"Over a period of at least 10 to 20 years, the Japan-U.S. security treaty is necessary for Japan," Kan said at a luncheon held by the United States Institute of Peace, a Washington think tank. "To maintain the treaty, it is necessary for Japan to provide a certain number of bases."

Challenging Hatoyama's idea, Kan, who is now on a six-day tour of the U.S., said the current form of the Japan-U.S. security treaty will disappear if the U.S. military ends its presence in Japan.

Kan said the 7th Fleet and the 5th Air Force should remain stationed in Japan, but called on the U.S. to move its 3rd Marine Corps from Okinawa to somewhere else in Asia or back to the U.S.