(CNN) -- Hundreds of law-enforcement officers were making arrests and executing search warrants Thursday in Arizona as part of an investigation into human smuggling, the Immigration and Customs Enforcement agency said. Authorities made at least 40 arrests in an investigation into the suspected smuggling of illegal immigrants in vans that took them from the border to Tucson and Phoenix, two officials with Immigration and Customs Enforcement said. Federal authorities scheduled a news conference for Thursday afternoon to discuss what they called "a massive, yearlong investigation targeting the infrastructure of several major Arizona-based human smuggling networks."
Crackdown under way as part of an investigation into human smuggling . Authorities made at least 40 arrests on Thursday, ICE officials said . Immigrants were shuttled in vans from the border to Tucson and Phoenix, officials said .