U.S. Immigration and Customs Enforcement agents raided seven Mississippi food processing facilities and arrested around 680 undocumented immigrants.

The operation was carried out by ICE Wednesday in coordination with the U.S. Attorney’s Office for the Southern District of Mississippi. Mike Hurst, the U.S. attorney for the district, said in the operation was of historic proportions and that it is “believed to be the largest single-state immigration enforcement operation in our nation's history.”

The raids were reportedly planned for months and were part of a long-term operation, ICE acting Director Matthew Albence told the Associated Press. About 600 agents swept the processing facilities of several companies across the state.

“This is a long-term operation that’s been going on. Our enforcement operations are being done on a racially neutral basis. Investigations are based on evidence,” Albence said after being questioned about the timing of the raids in relation to President Trump’s visit to El Paso, Texas.

Detainees were brought to the Mississippi National Guard in Flowood, which had set up 2,000 meals for those arrested while they are being processed for immigration violations.