The U.S. State Department considers Tamaulipas, where the two cities are located, to be the most dangerous state along the U.S.-Mexico border.
Tens of thousands of people a day are competing for 1,450 slots, according to U.S. Customs and Border Protection (CBP).
U.S. authorities temporarily suspended CBP One appointments in June in another Tamaulipas border city, Nuevo Laredo, due to "extortion and kidnapping concerns," the official said.
Juan Rodriguez, head of the Tamaulipas migrant services agency, said the agency was "attentive" to the issue.
Additional reporting by Jackie Botts in Mexico City, Daniel Becerril in Reynosa and Matamoros, and Kristina Cooke in San Francisco.
Persons:
Wong, Luis Miranda, Joe Biden's, Biden, Bertha Bermúdez Tapia, Miranda, Olivia Lemus, Lemus, Juan Rodriguez, Laura Gottesdiener, Ted Hesson, Mica Rosenberg, Beth Solomon, Jackie Botts, Daniel Becerril, Kristina Cooke, Mary Milliken, Suzanne Goldenberg
Organizations:
REUTERS, Reuters, U.S . Department of Homeland Security, U.S . State Department, New Mexico State University, Gulf Cartel, Northeast, U.S . Customs, Border Protection, CBP, DHS, Biden, The U.S . State Department, Carolina, Thomson
Locations:
U.S, Mexico, New Jersey, REYNOSA, Mexican, Reynosa, Venezuela, Carolina, Matamoros, Tamaulipas, United States, Washington, Nuevo Laredo, Central, Northern Mexico, Chicago, The, Honduran, Venezuelan, New York City, Mexico City, San Francisco