No proof fentanyl produced in Mexico, president says

"So far, we have not found that precursors arrive -- because most of the precursors come from Asia -- and that the whole process is manufactured here in Mexico," Claudia Sheinbaum told a news conference.

"The laboratories that have been dismantled in our country are mainly for methamphetamine or crystal (meth)," she added.

At the same time, Sheinbaum stressed that her government was committed to combating illegal drug distribution.

In recent weeks Mexican authorities have announced several major seizures of fentanyl, as well as chemical precursors.

The drug, a synthetic opioid 50 times more potent than heroin, has been linked to tens of thousands of overdose deaths in the United States.

Trump, who will begin his second term on January 20, has threatened to levy 25-percent tariffs on Mexican exports if the country fails to contain flows of drugs and migrants.

The US Drug Enforcement Administration (DEA) says that Mexican cartels are "at the heart" of a synthetic narcotics crisis in the United States.

The powerful Sinaloa Cartel "dominates the fentanyl market through its manipulation of the global supply chain and the proliferation of clandestine fentanyl labs in Mexico," it said in its 2024 National Drug Threat Assessment.

The cartel has been "producing bulk quantities of fentanyl since at least 2012," it said.

Outgoing US ambassador Ken Salazar told a news conference on Monday that he had no doubt the drug was manufactured in Mexico.

"I know what's happening, that there is fentanyl in Mexico, and I also know that it is produced here," he said.