MEXICO CITY Precursor chemicals used by Mexican cartels to make deadly opioid fentanyl do not come from China, the country's embassy in Mexico said on Tuesday, rejecting U.S. officials' claims.

The embassy said in a statement that China had a number of measures in place to prevent the trafficking of substances used to make illegal drugs, and said the U.S. was "blindly shirking its responsibilities" by not taking domestic action.

(Reporting by Kylie Madry)