The Mexican government says two US agents who died last weekend in a car crash had not been authorised to operate in the country.

The officials, who reportedly worked for the CIA, had taken part in a raid on suspected drug labs in the northern state of Chihuahua before their vehicle skidded off a mountain road and exploded.

Following an investigation ordered by President Claudia Sheinbaum, Mexico's security ministry stated that neither had formal accreditation to participate in operational activities and that federal authorities had not been informed of their presence.

The incident comes amid fraught relations between Mexico and the US on various issues, including counter-narcotics.

Sheinbaum has faced pressure from US President Donald Trump to crack down on drug trafficking but has declined offers for US-led operations in Mexico, asserting that foreign officials can only operate with prior federal approval.

According to immigration records, one agent entered Mexico as a visitor, while the other had a diplomatic passport. Neither had formal accreditation to participate in operations, as per Mexican law.

The crash occurred on 19 April when a convoy returning from an operation targeting methamphetamine labs veered off the road and plunged into a ravine, leading to the deaths of two agents from the Chihuahua State Investigation Agency as well.

Chihuahua State Attorney General César Jáuregui stated at a news conference that the US officials were instructor officers from the US embassy engaged in training work with Mexican authorities. However, Sheinbaum emphasized that there were no joint operations on land or in the air currently occurring.

In light of this crash, concerns have emerged regarding the previous covert operations by the CIA in Mexico, aimed at tracking drug traffickers, and Sheinbaum's government continues to assert its sovereignty while cooperating with the US on certain security matters.