Foreign Minister Makiko Tanaka unofficially voiced concern over U.S. missile defense plans in a series of recent diplomatic talks with her counterparts from Italy, Germany and Australia, Japanese government sources said Friday.

Tanaka's alleged comments could stir up controversy because they apparently contradict the government's official position that the nation "understands" the new U.S. strategy without actively supporting it.

"I wonder if the missile defense is necessary," Tanaka was quoted as telling Italian Foreign Minister Lamberto Dini, who sat next to her during a working luncheon for foreign ministers at the Asia-Europe Meeting in Beijing on May 25. "Japan and Europe should cooperate in urging the United States not to go too far."