Beijing's view of American power as less of a constraint in Asia is boosting its willingness to pursue more aggressive risk-taking, putting a damper on Washington's rebalance to the region, a major independent U.S. report has warned.

The report, conducted for the U.S. Defense Department by the Center for Strategic and International Studies (CSIS) and released last week, claims that — despite the U.S. rebalance — Beijing's tolerance for risk has exceeded most expectations.

This has been most evident in the disputed waters of the South China Sea, where Beijing has constructed military airfields and facilities on reclaimed islands in the Spratly archipelago despite rival claims by neighbors.