The U.S. Consulate General in Matamoros issued a Friday security alert warning the public of organized kidnappings in Reynosa.

The kidnappings are happening on intercity buses departing Reynosa, Tamaulipas, the alert stated.

“These kidnappings appear to specifically target passengers with connections to the United States, including U.S. citizens and residents,” the alert stated. “The kidnappers typically demand ransoms of thousands of dollars for each victim.”

Tamaulipas remains under a Level 4 travel advisory by the U.S. Department of State warning people to not travel due to crime and kidnappings in the area.

The warning says people should avoid traveling by bus in or through Tamaulipas, and urged the public to be aware of their surroundings and to notify friends and family of their safety.