Mexican President Claudia Sheinbaum has ordered an investigation into the role played by two US officials in a counter-narcotics operation in the northern state of Chihuahua. The two died alongside two Mexican officials when their car crashed on their way back from an operation to destroy illegal drug labs, Chihuahua officials said.

Sheinbaum said that neither she nor senior members of the federal security team had been informed about any joint US-Mexican operations. The Mexican leader has been adamant that foreign officials can only operate on Mexican soil if given prior clearance at the federal level.

Sheinbaum has come under pressure from her US counterpart, Donald Trump, to do more to stem the flow of drugs from Mexico to the United States but she has insisted that Mexico's sovereignty cannot be breached. On Monday, Sheinbaum reiterated, we did not have knowledge of any direct work between Chihuahua state and personnel from the US embassy.

She further stated that the government needed to understand the circumstances under which this was taking place, and then assess the legal implications. According to a Chihuahua state official, the US officials and their Mexican counterparts died when their vehicle skidded off the road into a ravine and exploded.

The US ambassador in Mexico, Ronald Johnson, described the two US citizens as US embassy personnel. Chihuahua State Attorney-General César Jáuregui indicated in a press conference that they were instructor officers engaged in training as part of a normal exchange with US authorities.

The accident happened as they were driving back from an operation involving the destruction of clandestine laboratories for synthetic drugs.