The U.S. military will probably scale back plans to build key bases in Japan and Guam because of political obstacles and budget pressures, according to U.S. and Japanese officials, complicating the Obama administration's efforts to strengthen the presence of U.S. forces in Asia.

Under a deal announced Wednesday with Japanese officials, the U.S. government said it will accelerate plans to withdraw 8,000 marines from Okinawa. The decision came after several years of stalled talks to find a site for a new marine base nearby.

Washington's inability to resolve its basing arrangements in Okinawa, as well as the rising price tag of a related plan for a $23 billion military buildup on Guam, underscore the challenges facing the Obama administration as it seeks to make a strategic "pivot" toward the Pacific after a decade of fighting wars in Iraq and Afghanistan.