Two CIA officers were killed in Mexico in a fiery car crash after meeting with Mexican authorities that busted one of the 'largest ever drug labs' in the nation, according to reports.

The officers, who have not been named, died along with the area's chief police investigator and his bodyguard in the state of Chihuahua on Sunday. 

Mexican officials said the car swerved off the road and exploded when it fell down a ravine.  

The Americans were initially identified as US embassy officials, however sources told the Washington Post that they worked for the CIA.

They reportedly worked with the agency as part of an expanded American role in battling drug trafficking over the southern border, the outlet reported. 

The crash unfolded as the four victims were reportedly returning from a meeting with Mexican officials to discuss a raid that took place the next day on a huge drug facility in a remote area of the state, near the US-Mexico border. 

Chihuahua’s attorney general, Cesar Jauregui Moreno, described the lab as 'perhaps one of the largest ever located' and told Mexico’s El Universal newspaper that the Americans did not directly participate in the raid. 

Mexican President Claudia Sheinbaum launched an investigation into the crash, vowing to uncover if the alleged CIA involvement violated national security laws. 

The Mexicans killed in the crash were identified as Pedro Ramon Oseguera Cervantes, the regional director of Chihuahua’s State Investigation Agency (AEI), and his bodyguard. 

Sources told the Post that the CIA officers' involvement in the drug operations came amid a broader push from CIA director John Ratcliffe to take a more aggressive stance against the narcotics trade. 

This has reportedly seen the agency increase its intelligence sharing with Mexican authorities in hopes of cracking down on trafficking across the border. 

President Trump has also repeatedly threatened to take dramatic action against Mexico's powerful cartels since retaking office and has launched a number of controversial air strikes on alleged drug trafficking boats in South America and the Caribbean.  

Officials said the joint US-Mexican operations led to the location of the drugs lab, however only Mexican authorities were involved in busting the lab on April 18. 

Images from the raid last week showed a large number of canisters and drug equipment used for manufacturing methamphetamine scattered around the open-air lab. 

Speaking on Monday following the crash, Sheinbaum said she was not informed that any US officials would be taking part in the raid on the huge drug lab. 

'We were unaware of any direct collaboration between the state of Chihuahua and personnel from the US Embassy in Mexico,' the Mexican president said. 

'The relationship is federal, not state. They must have authorization from the federal government for this collaboration, which necessarily takes place at the state level, as established by the Constitution.' 

US involvement in Mexico's cartels and drug trade has become a contentious issue in the country due to a long history of what Mexican officials say are violations of its jurisdiction. 

Sheinbaum said she will be demanding answers over the drug raid, insisting she is not aware of any 'joint operations on land or in the air' involving US authorities such as the CIA.