BEIJING, Aug 10 (Reuters) - China's commerce ministry said it is "gravely concerned" about the United States' signing of an executive order that will prohibit some new U.S. investment in China in sensitive technology, and said it reserves the right to take measures.

It said it hopes the U.S. will respect laws of the market economy and the principle of fair competition, and refrain from "artificially hindering global economic and trade exchanges and cooperation". (Reporting by Beijing newsroom; Writing by Liz Lee; Editing by Christopher Cushing)