Mexican authorities report that the Venezuelan prison gang Tren de Aragua is expanding its influence along the U.S.-Mexico border by deepening ties with local criminal groups.

The gang reportedly facilitates illegal migration from Central and South America to Juárez, charging migrants as much as $15,000 for so-called “safe passage.” Many of these migrants are later kidnapped by local gangs, who demand additional ransoms from families in the U.S. or abroad.

Tren de Aragua has also been linked to the murder of a Mexican immigration officer and to recent operations in which migrants were rescued from stash houses. Authorities continue to monitor the gang’s cross-border activities closely.