US officials suspended government activities and travel to Mexicali, Mexico, on 25 August after receiving information about a potential security threat. The alert matters because Mexicali is a major border crossing opposite Calexico, California, with significant daily movement of people and goods between the two countries.

The reported threat concerned a possible armed attack by the criminal group Los Rusos on law-enforcement facilities, following the seizure of around 265 pounds of fentanyl in the city, estimated at four million doses. Americans were advised to avoid government buildings, remain alert, follow Mexican authorities’ instructions and monitor local media; it was unclear whether the alert was still in force. In 2025, more than 5.4 million vehicles and 3.1 million pedestrians entered the US through Calexico.