""Red alerts should be going off in all boardrooms right now about risks in China," the source, who did not wish to be identified due to the sensitive nature of the matter, said.

China has said it welcomes foreign trade and investment but stressed that security comes before development.

U.S. businesses operating in China are increasingly pessimistic about their prospects in the world's second-largest economy, according to a survey released this month by the American Chamber of Commerce in China.

Two-thirds of the respondents cited rising U.S.-China tensions as the top business challenge."

China detains staff, raids office of US due diligence firm Mintz Group (yahoo.com)