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 said "we did not have knowledge of any direct work between Chihuahua state and personnel from the US embassy". She also said 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 two US nationals and two members of the Chihuahua State Investigation Agency (AEI) died on Sunday morning when the car they were travelling in skidded off the road and fell into a ravine, where it exploded. The US ambassador in Mexico, Ronald Johnson, described the two American citizens as "US embassy personnel". On Tuesday, the Washington Post reported that the two US officials who died worked for the CIA as part of a significantly expanded role in battling narcotics trafficking in the Western Hemisphere. (BBC)