The United States warned China on Wednesday, June 22 against taking "additional provocative actions" following an impending international court ruling on the South China Sea that is expected to largely reject Beijing's broad territorial claims, Reuters reports.

A senior State Department official voiced skepticism at China's claim that dozens of countries backed its position in a case the Philippines has brought against Beijing and vowed that Washington would uphold U.S. defense commitments.

Colin Willett, deputy assistant secretary of state for East Asia, said Washington had "a lot of options" to respond to any such Chinese moves in a region she said was vital to U.S. interests. She also made clear that with a ruling expected possibly within weeks, the United States was working to rally sometimes wavering allies and partners in the region to ensure a unified front.

How Washington handles the aftermath of the ruling is widely seen as a test of U.S. credibility in a region where it has been the dominant security presence since World War Two but is now struggling to contain an increasingly assertive China.

"We, the United States, do have very clear national interests in the area," Willett told Reuters.

"We have an interest in upholding our defense commitments and our security partnerships."

The Philippines is contesting China's claim to an area shown on its maps as a nine-dash line stretching deep into the maritime heart of Southeast Asia, covering hundreds of disputed islands and reefs and encompassing a vital global trade route.

The consensus among officials and analysts inside and out the region is that the ruling will go largely against Beijing.