Travel and official activity for US government employees in Nogales, Mexico, have been restricted following an unspecified security threat reported in the border city.The US Embassy and Consulates in Mexico issued the alert on Saturday. The US Consulate General in Nogales said in a statement: “Due to threat information, U.S. government activities in, and travel to, Nogales have been restricted to essential movement during daylight hours only.”“We are alerting U.S. citizens of this threat and change in posture,” the statement added.The consulate did not identify the threat or provide details about the information behind the warning.Mexican authorities said they had contacted US consular officials after the alert was issued. Sonora’s State Security Board said it had not received information pointing to a specific threat or an immediate danger to the public.The state security agency said preventive operations would continue in Nogales.The warning comes with Sonora already classified by the US State Department as a Level 3 destination, meaning Americans are advised to “Reconsider Travel.”US citizens in Nogales have been urged to remain alert, monitor local news and follow instructions from Mexican authorities. The guidance also advises people to seek shelter if an incident occurs and inform family or friends of their safety.US Rep. Andy Biggs, a Republican from Arizona, urged Americans in and around Nogales to follow the government’s safety guidance.“We are praying for the safety of US citizens and personnel who may be in harm’s way,” Biggs said in a post on X.The nature of the threat that led to the latest restrictions has not been disclosed.