The foreign ministry, in a statement attributed to spokeswoman Hua Chunying, said Xinjiang is China's internal affair and urged the U.S. to correct its mistakes and stop the bill from becoming law.
China will respond further depending on the development of the situation, the statement said.
The U.S. House overwhelmingly backed the bill in a vote on Tuesday. It still has to be approved by the Senate before being sent to President Donald Trump, and the White House has yet to say whether Trump would sign or veto it.