Mexican federal and Tamaulipas state authorities in Reynosa detained Alexander "N," a presumed member of an armed group operating in the area.

The detention led to eight roadblocks early Monday morning across Reynosa, Gustavo Diaz Ordaz, south of Rio Grande City and Miguel Aleman, south of Roma. At least 10 locations with surveillance cameras were shot at, according to Tamaulipas state police. Officials first reported a roadblock along Highway 2D near Los Guerra, across from Fronton.

Nearly 24 hours after the arrest, the U.S. Consulate in Matamoros posted a security alert on social media saying U.S. government employees had been ordered to avoid Reynosa.

In weeks prior to the arrest, authorities say several banners with threats directed towards emergency services were hung in different locations around Reynosa. Officials say the banners were signed by Alexander "N."

Investigators from Mexico's Attorney General's Office said they received an anonymous tip about armed people keeping drugs and weapons inside a home in the Vicente Guerrero neighborhood of Reynosa.

Through a judicial search warrant, investigators entered the home and seized an assault rifle, cartridges, chargers, tactical gear, four vehicles, a cell phone and documentation.

Federal investigators led Monday's operation in coordination with the Federal Ministerial Police and federal forensic investigators.

Personnel from Mexico's Safety and Citizen Protection Secretariat in coordination with the Federal Ministerial Police, the National Defense Secretariat, the National Guard, Mexico's Attorney General's Office and Tamaulipas state police were on the scene.

By noon on Monday, state police reported no roadblocks on Tamaulipas state highways, while authorities continued their patrols.