Japanese opponents of the war in Iraq demonstrated in central Tokyo on Wednesday, as government ministers assured the top U.S. general they would continue to provide military back-up.

About 1,500 protesters marched through the streets of the Japanese capital, holding banners reading "Stop the Occupation of Iraq" and chanting anti-war slogans to mark four years since the U.S.-led invasion.

"I want to do whatever I can to stop the war in Iraq, as well as to stop the Japanese government from changing the constitution to allow troops to be sent abroad," said 40-year-old office worker Yoko Hinata.

Japan withdrew its 600 ground troops from southern Iraq last year after a non-combat reconstruction mission which lasted more than two years. But about 200 air force personnel remain in neighboring Kuwait, from where they airlift supplies to U.S. forces and their allies.

Itself a staunch U.S. ally, Japan's postwar pacifist constitution restricts its participation in military activities overseas, but Prime Minister Shinzo Abe wants to rewrite the document to make such dispatches easier.

Foreign Minister Taro Aso told the visiting top U.S. military officer, Marine Gen. Peter Pace on Wednesday that Japan wanted to continue the back-up mission, whose legal mandate expires in July.

Japan's ruling Liberal Democratic Party yesterday agreed to recommend extending the mandate by two years, clearing the way for the legislation to pass, given the party's parliamentary majority.

Defense Minister Fumio Kyuma told Pace the government was working toward an extension, Kyodo news agency said.

A recent poll in the Asahi Shimbun daily showed 75 percent of respondents thought the Iraq war had been a mistake. Sixty-nine percent said they wanted the air force troops to be withdrawn.