A Chinese official said on Friday that China will never send military forces to the scene of an increasingly ugly spat with Vietnam over an oil rig in the South China Sea and accused Hanoi of trying to force an international lawsuit.

A senior U.S. official in Washington dismissed the Chinese statement as "patently ridiculous" and said Beijing had been using air force and navy as well as coast guard assets "to intimidate others."

Scores of Vietnamese and Chinese ships, including coast guard vessels, have squared off around the rig despite a series of collisions after the Chinese platform was towed into disputed waters in early May.