RIVERSIDE COUNTY, Calif. () cameras were the only ones on the ground as a massive surge of law enforcement gathered in Southern California to dismantle three massive illegal marijuana grow operations on federal land, with one of them stretching more than 250 acres.

The U.S. Drug Enforcement Administration says the grow operations are located on federal land and not controlled, as they’re operating outside of the law despite the drug’s legality in California. As with many illegal grow operations, employing those with undocumented U.S. legal status is also rampant.

“Crime follows crime. So in order to get these criminal grows productive, they have to reach out to undocumented workers in order to get it done,” said DEA agent Anthony Chrysanthis. “So we are anticipating there being some undocumented workers on scene. We have plenty of resources here available to interview them, find out their story, find out how they got here, see how they were trafficked, and then pass those leads on.”

Just about every federal agency was on the scene, and the DEA says it’s the largest law enforcement collaboration in recent history in the region, with upwards of 500 agents, officers, and soldiers 325 of them from the California National Guard. Roughly 100 armored vehicles were also involved in the operation.

Multiple arrests were made in the operation, according to law enforcement sources.