The US Drug Enforcement Administration on Monday announced “Project Portero,” a cross-border crackdown it said would be carried out “side by side with our Mexican partners” to dismantle cartel gatekeepers who control fentanyl, methamphetamine and cocaine smuggling routes along the Southwest border. DEA Administrator Terrance Cole said the multi-week programme would train Mexican investigators at a US intelligence centre and pool resources from agencies such as the FBI, ICE and Customs and Border Protection. Mexican President Claudia Sheinbaum rejected the claim of a bilateral accord the following day, telling reporters: “There is no agreement with the DEA.” She acknowledged that four Mexican police officers had attended an intelligence workshop in Texas but insisted no wider collaboration had been authorised and that any joint announcement must be cleared by her government. The DEA has maintained that the operation is being coordinated with its Mexican counterparts, highlighting persistent friction in security cooperation after Washington’s decision earlier this year to designate several Mexican cartels as terrorist organisations and expand sanctions. The disagreement leaves the future of Project Portero uncertain even as US authorities step up pressure to curb fentanyl flows that officials say kill tens of thousands of Americans annually.