U.S. to back nations whose South China Sea claims China violated

"We will then go use the tools that we have available and we will support countries all across the world who recognize that China has violated their legal territorial claims as well – or maritime claims as well," Pompeo told reporters.

"We will go provide them the assistance we can, whether that’s in multilateral bodies, whether that's in ASEAN, whether that's through legal responses, we will use all the tools we can," he said, referring to the 10-member Association of Southeast Asian Nations (ASEAN).