China says Trump's claims about fentanyl origin are false

China said Tuesday that it's not the source of the fentanyl that's killing Americans, contrary to President Donald Trump's recent tweets blaming China for the drug deaths.

At a briefing for the National Narcotics Control Commission, China reiterated that it is making extensive efforts toward controlling the synthetic opioid and should not be labeled the main origin of fentanyl to the U.S.

The drug often comes through the mail or across the Mexico border. It can be stronger and more lethal than heroin and is responsible for tens of thousands of American drugs deaths each year.

Amid the latest round of tariff increases between the two countries last month, Trump blasted China in a Twitter thread in which he vowed to order all postal carriers to "SEARCH FOR & REFUSE all deliveries of fentanyl from China (or anywhere else!)."