MEXICO CITY — Mexico's government and the White House sparred on Wednesday over the deaths of two US citizens in connection with an anti-drug raid, after US media reported the officials were CIA personnel.

Two US people died in a car accident on Sunday in the northern state of Chihuahua in Mexico. Two Mexican investigators also died in the crash.

The CBS network and other US media have reported that the two US citizens, who have not been identified, worked for the Central Intelligence Agency.

The US ambassador to Mexico on Sunday said that only US embassy employees died in a car accident.

Mexican President Claudia Sheinbaum said on Wednesday that the federal government was unaware of the CIA agents taking part in an anti-narcotics operation in northern Mexico to dismantle a clandestine drug lab.

The presence of US agents in an operation against organized crime in Chihuahua, a state bordering Texas, "is something that should not be taken lightly", as it is a matter of national security and sovereignty, said the president.

"We are verifying whether they were accredited or not," she said at Wednesday morning's news conference regarding this case.

Sheinbaum emphasized that, given this potential violation of national laws, the Foreign Ministry sent a letter to the US ambassador to Mexico requesting all relevant information and stating that such actions are not part of established security protocols.

"Any relationship with the US government, particularly on security matters, must go through the federal government," she said, adding that there had been "no knowledge" of the agents' participation.

She also stressed that no US government agents should operate in Mexico without authorization.

On Wednesday afternoon, White House Press Secretary Karoline Leavitt pushed back on Sheinbaum's comments, saying that US efforts to counter cartels in Mexico "are not only a benefit to the American people, but to her people as well".

Drug trafficking

"I think the president (Donald Trump) would agree that some sympathy from Claudia Sheinbaum would be well worth it for the two American lives that were lost, considering all that the United States of America is doing currently under this president to stop the scourge of drug trafficking through Mexico to the United States," Leavitt said in an appearance on Fox News.

The US administration has provided very few comments on the incident since the Sunday crash. The CIA declined to comment on Wednesday.

The Chihuahua state prosecutor said the US citizens had been returning from a raid of clandestine drug labs when their car, which was in a five-vehicle convoy, skidded off the road and into a ravine. The convoy was also carrying soldiers and members of the Chihuahua State Investigation Agency.

The US agents killed were "instructor officers" who "were carrying out training tasks" as part of anti-drug cooperation, according to prosecutor Cesar Jauregui.

On-the-ground cooperation between US law enforcement and Mexican security forces is rare and a sensitive topic in the country.

Sheinbaum has resisted the US administration's threats to use airstrikes or ground troops to fight Mexican cartels, instead promoting intelligence sharing with the United States while local security forces attack crime groups.

Agencies - Xinhua