More than 600 suspected gang members have been arrested in the Homeland Security Department’s latest crackdown on street gangs, according to Immigration and Customs Enforcement officials.

ICE agents, along with local authorities in 179 cities, arrested 638 suspected gang members over a monthlong period in March and April, The Associated Press reports. More than 400 of those arrested had violent criminal histories. Seventy-eight were arrested on federal charges, and 113 were arrested on administrative immigration charges.

The crackdown, “Project Southbound,” is part of a larger ICE initiative that started in 2005 to target street gangs with international ties. ICE says it has arrested more than 33,000 suspected gang members since the initiative started.