TWO United States officials killed in a vehicle crash as they returned from destroying a drug lab in northern Mexico over the weekend were working for the CIA, according to a US official and two other sources.

Two Mexican investigators also were killed in the crash, which Mexican authorities said occurred while the convoy was returning from an operation to destroy drug labs of criminal groups.

There have been discrepancies in the public accounts of what happened from US and Mexican officials, which experts say underscores heightened US involvement in clandestine operations in Mexico and across the region.

The CIA’s involvement was confirmed on Tuesday by the three sources.

That the US officials worked for the CIA was reported earlier by The Washington Post.

The incident has reignited a debate over the extent of US involvement in Mexico’s security operations as Mexican President Claudia Sheinbaum faces extreme pressure from the US. 

President Donald Trump’s administration has cracked down on cartels and has taken a more aggressive stance toward Latin America than any leader in recent US history.

This includes the deadly US illegal and unprovoked attack on Venezuela, where Venezuela’s President Nicolas Maduro and First Lady Celia Flores were kidnapped, blockading oil shipments to Cuba and launching joint military operations in Ecuador, a country also marked by criminal violence.

The CIA officers were initially identified as US embassy personnel by US ambassador to Mexico Ron Johnson, who is himself a former CIA employee.

The embassy, State Department and CIA declined to comment.

Ms Sheinbaum said she knew nothing of a joint operation between Chihuahua’s government and the US despite reports that the Mexican army was also involved in the raid on the lab.

She told a press briefing on Tuesday that she didn’t know if the officials were part of the CIA but acknowledged that state officials and the US “were working together.”