The United States has expressed concern about Japan's desire to acquire the ability to attack enemy bases in an overhaul of defense policies pursued by Prime Minister Shinzo Abe, a government source said in Tokyo.

One of the American officials attending bilateral talks on foreign and defense policy cooperation late last month in Tokyo asked the Japanese side to consider the possible negative fallout on neighboring countries if the Abe administration embarks on such a policy shift, the source said Tuesday.

The U.S. official conveyed Washington's message that Tokyo should not further worsen relations with China and South Korea, which have been plagued for months by territorial rows, as well as the issue of Japan's wartime aggression.