Federal immigration authorities arrested nearly 500 illegal aliens from over 40 countries in a four-day operation that concluded on Wednesday.

Dubbed operation “Safe City,” U.S. Immigration and Customs Enforcement (ICE) and Enforcement Removal Operations (ERO) teams took 498 individuals into custody on federal immigration charges. The operation targeted areas where ICE agents are “denied access to jails and prisons to interview suspected immigration violators or jurisdictions where ICE detainers are not honored,” ICE said in a statement.

Authorities prioritized illegal aliens with criminal convictions, pending criminal charges, gang members, and fugitives in the following areas: Baltimore (28), Cook County, Illinois (30), Denver (63), Los Angeles (101), New York (45), Philadelphia (107), Portland, Ore. (33), Santa Clara County, Calif (27); and Washington, D.C. (14) and the state of Massachusetts (50).

Acting ICE Director Tom Homan noted the importance of the operation in keeping American’s safe from criminal illegal aliens sheltered in “sanctuary” cities and states.

“Sanctuary jurisdictions that do not honor detainers or allow us access to jails and prisons are shielding criminal aliens from immigration enforcement and creating a magnet for illegal immigration,” Homan said. “ICE’s goal is to build cooperative, respectful relationships with our law enforcement partners to help prevent dangerous criminal aliens from being released back onto the streets. Non-cooperation policies severely undermine that effort at the expense of public safety.”

Out of the 498 arrested, 317 had prior criminal convictions, 68 were immigration fugitives, 104 were previous deported criminal illegal aliens, and 18 were known gang members. Those who illegally returned to the U.S. after removal are subject to immediate removal, while the remaining illegal aliens will face an immigration judge for removal proceedings.