Since January, U.S. Immigration and Customs Enforcement has arrested about 250 foreign students at a fake university in Michigan. It's part of a sting operation by federal agents.

The University of Farmington was opened in 2015 as a guise by ICE officials. It was created to entice foreign-born students, mostly from India, who had arrived legally in the U.S. on legitimate student visas.

But the government says the phony university was a "pay-to-play" scheme the students used to remain in the U.S. under a student visa. Some of the students were arrested and deported while others await trial in the states.

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The Detroit Free Press reported that nearly 80% of those have voluntarily left the country. The Homeland Security Investigations Detroit office told the newspaper that about half of those remaining have received final orders of removal.

An ICE spokesperson told CBS News that this type of operation serves as a deterrent because it reminds students to be careful to follow the law while studying in the U.S.

But several lawmakers took to social media to express outrage at the operation, including 2020 presidential candidate Elizabeth Warren.

This is cruel and appalling. These students simply dreamed of getting the high-quality higher education America can offer. ICE deceived and entrapped them, just to deport them. https://t.co/t6kQLiV5oh — Elizabeth Warren (@ewarren) November 27, 2019

Actress Alyssa Milano also reacted to the sting operation.

OH MY GOD. ICE has arrested about 250 students who were enrolled at a fake university set up by ICE to lure in students.https://t.co/2P8iZtnMGB — Alyssa Milano (@Alyssa_Milano) November 27, 2019

The Detroit Free Press reported that seven of eight recruiters charged by the government pleaded guilty and have been sentenced. The eighth person will be sentenced in January.

Assistant U.S. Attorney Brandon Helms defended the operation, the newspaper reported.

"Their true intent could not be clearer," Helms wrote in a sentencing memo this month for one of the recruiters, the newspaper reported. "While 'enrolled' at the University, one hundred percent of the foreign citizen students never spent a single second in a classroom. If it were truly about obtaining an education, the University would not have been able to attract anyone, because it had no teachers, classes, or educational services."