The Trump administration has moved ahead with a surveillance drone sale to four U.S. allies in the South China Sea region as acting Defense Secretary Patrick Shanahan said Washington will no longer "tiptoe" around Chinese behavior in Asia.

The drones would afford greater intelligence gathering capabilities potentially curbing Chinese activity in the region.

Shanahan did not directly name China when making accusations of "actors" destabilizing the region in a speech at the annual Shangri-La Dialogue in Singapore on Saturday but went on to say the United States would not ignore Chinese behavior.