The United States plans to maintain a significant Marine presence on Okinawa, consisting of two units, sources told the Yomiuri Shimbun. The United States informed Japan of the decision during a review of a 2006 Japan-U.S. agreement Monday and Tuesday. The decision involves about 10,000 of the 18,000 Marines currently stationed in Okinawa prefecture -- the III MEF Command Element, considered the front-line force against China and North Korea. The remaining combat forces are to be relocated to Guam.