The U.S. Treasury said on Thursday it has sanctioned the top leaders of Venezuelan prison gang Tren de Aragua for being involved in criminal activities including illicit drug trade, human trafficking and money laundering.

The group has been linked to human trafficking networks that move migrants north through Central America and Mexico, with stops in border cities like Tapachula and Tijuana — and eventual arrivals in U.

The U.S. has long targeted the Venezuelan gang Tren de Aragua, but the Trump administration has stepped up those efforts.

The sanctions apply to kingpin Hector “Niño” Guerrero and his top five lieutenants. Guerrero has a $5 million reward on his head after taking Tren de Aragua from a prison gang in Venezuela to a full-blown foreign terrorist organization with tentacles across the U.