Republican lawmakers in the U.S. reacted with outrage Friday to Mexican President Andrés Manuel López Obrador's claim that his country plays little role in the fentanyl crisis killing tens of thousands of Americans every year.

"Clearly the President of Mexico doesn't care that 70, 000 people died of fentanyl overdose in America last year," said Sen. Rick Scott (R-Florida) in an interview with NPR.

"He's allowed his border to be controlled by the cartels and he doesn't care."

During a lengthy press conference Thursday, López Obrador disputed whether Mexico plays a significant role in illicit fentanyl trafficking.

"Here, we do not produce fentanyl, and we do not have consumption of fentanyl," López Obrador said.

He also blamed the overdose crisis in the U.S. on "social decay" in American society.

"We deeply lament what's happening in the United States - but why don't they fight the problem ... and more importantly why don't they take care of their youth?"

But most drug policy experts and officials with the U.S. Drug Enforcement Administration say there's no question Mexican drug cartels are fueling the explosion of deadly fentanyl on American streets.

U.S. law enforcement officials say in recent years, Mexican officials have refused to cooperate on efforts targeting fentanyl labs inside Mexico.

"We are not getting information on fentanyl seizures; we are not getting information on seizures of precursor chemicals," said DEA chief Anne Milgram during a Senate hearing last month.

Obrador's comments follow demand for military action by GOP lawmakers

In recent days, Republican lawmakers have suggested the death toll is so dire, U.S. military should play a role inside Mexico helping disrupt traffickers and drug gangs.

"We're going to unleash the fury and might of the United States against these cartels," said Sen. Lindsey Graham (Republican - SC) at a press conference Wednesday.

Republicans have also called on the U.S. to designate drug cartels as international terrorist organizations.

During his press conference Thursday, López Obrador mocked those proposals as "Robocop" and "authoritarian" thinking.

He said a U.S. military presence inside his country would represent an unacceptable infringement of Mexican sovereignty.

"We want to be clear about our position," López Obrador said. "We will not allow any foreign government to mingle, and let alone foreign armed forces, in our territory."

In a statement sent to NPR Friday afternoon, National Security Council spokesperson Adrienne Watson said the Biden administration is not "considering military action in Mexico."

Watson said the U.S. and Mexico will "continue to work this problem together," adding the two countries have "robust law enforcement cooperation."

But while López Obrador repeatedly singled out Republican proposals for criticism, his comments also appeared to put him at odds with the Biden administration.

U.S. officials have repeatedly urged Mexico to do more to target fentanyl and methamphetamine labs and cartel operations.

Just hours before the Mexican president spoke, U.S. Ambassador Ken Salazar tweeted that the two countries "must coordinate efforts against illicit fentanyl production and trafficking."

In recent days, the Biden administration has begun rolling out more high-tech surveillance equipment at border crossings designed to detect fentanyl.

During his state of the union address, Biden also called for a "surge" along the U.S.-Mexico border to reduce fentanyl trafficking.

A call for the U.S. to disrupt fentanyl trafficking even if that affects ties with Mexico

But many drug policy experts question whether any of these measures will significantly reduce the availability of fentanyl on American streets.

Most fentanyl comes in through legal ports of entry, smuggled in the roughly 70 million cars and trucks that transit the border every year.

Detecting and halting drug shipments hidden among that traffic is a daunting challenge.

It's also unclear whether the Mexican government has the firepower and institutional strength to fight the cartels, which are heavily armed and well organized.

The depths of the problem were illustrated just last month, when the U.S. prosecuted a former top Mexican law enforcement official, Genaro Garcia Luna.

Garcia Luna was a partner the U.S. trusted in the drug fight for years but it turned out he was working for one of the major cartels.

Still, with fentanyl deaths this high, there's pressure in Washington, D.C., to do something to disrupt fentanyl trafficking, even if it also means disrupting trade and diplomatic ties with Mexico.

"If it means we've got to slow down the crossings on the Southern border, we're going to have to slow down crossings on the Southern border," said Sen. Scott.

"They're killing our kids. So if that means we do less trade with Mexico, we do less trade with Mexico."

Digital story edited by Maquita Peters.