(This April 6 story has been corrected to update the CDC data on fatalities to more than 70,000 in 2021 from all synthetic opioids, not more than 100,000 in fiscal 2022 from fentanyl, in paragraph 6)
BEIJING (Reuters) - There is no such thing as illegal trafficking of fentanyl between China and Mexico, China's foreign ministry said on Thursday, responding to a letter from the Mexican president asking Beijing to help limit illicit flows of the deadly drug.
China has not been notified by Mexico about any seizure of fentanyl from China, ministry spokesperson Mao Ning said at a regular briefing.
"U.S. needs to face up to its own problems and take more substantive measures to strengthen regulation within its borders and reduce demand," Mao said, referring to drug abuse as a problem "made in the U.S.".
Mexico's president said on Tuesday he had written to Chinese president Xi Jinping, urging him to help control shipments of fentanyl as he fended off criticism in the U.S. that Mexico is not doing enough to stop trafficking of the synthetic opioid.
Fentanyl, widely used in hospitals during anaesthesia and for pain relief, has become a major black market narcotic in the United States. Mexican drug cartels have increasingly taken part in the illegal business.
There were more than 70,000 reported overdose deaths involving synthetic opioids in 2021, according to data from the U.S. Centers for Disease Control and Prevention.
President Andres Manuel Lopez Obrador defended in the March 22 letter efforts to curb supply of the drug, while rounding on U.S. critics, some of whom want Washington to intervene militarily in Mexico.
The letter and China's response did not mention supplies of the precursor chemicals used to make the powerful sedative.
The U.S. Drug Enforcement Agency says both finished fentanyl and precursors are transported from China to Mexico, the United State and Canada, often by international mail.
(Reporting by Yew Lun Tian; Writing by Liz Lee; Editing by Frank Jack Daniel)