WASHINGTON, Aug. 7 (Xinhua) -- U.S. immigration agents on Wednesday raided multiple food processing plants in southern state Mississippi, taking about 680 immigrants into custody, the authorities said.

The early-morning raids were part of a large-scale operation targeting owners as well as employees and were planned months ago, according to local media reports, noting that most of the arrested are Latino workers.

The raids happened just hours before President Donald Trump was scheduled to visit El Paso, Texas, a majority-Latino border city where a 21-year-old white male opened fire at shoppers at a Walmart on Saturday, leaving 22 dead and more than 20 injured. The suspect, identified as Patrick Crusius, was taken into custody and is believed to have acted on anti-immigrant sentiment.