Illinois universities are speaking out against President Donald Trump’s sweeping travel ban that has left some students and professors stranded abroad.

The University of Illinois System put out a statement Monday saying its three campuses are “greatly concerned” about the ban and “strongly recommend that students and scholars who might be affected defer travel outside the U.S.” School officials say they’re working with those affected and offering resources.

University of Chicago President Robert Zimmer says the ban puts “unnecessary restrictions on the flow of talented scholars and students” into the U.S. and damages the school’s ability to “fulfill its highest aspirations.”

He and the school’s provost, Daniel Diermeier, also released a letter to President Trump dated Monday, which read in part:

“We understand that the motivation for recent actions concerning immigration has been a concern for national security and the threat of terrorism. . . . But we strongly urge that the methods of doing so be examined and thought through carefully, so that the many people who can add so much to the country through immigration have the opportunity to do so, and those who are doing so already are treated with the respect and dignity they deserve.”

Northwestern University President Morton Schapiro says the Evanston school “will take the necessary actions to protect our students, faculty and staff.” He says Northwestern is “committed to being a welcoming and inclusive community.”

And in a message posted the Loyola University Chicago website, President Jo Ann Rooney called Trump’s executive orders “unprecedented” and said they “have left many outraged, confused, and fearful of their safety and future. I want to reinforce that we are a community made stronger because of our diversity. All are equally valued, regardless of faith tradition, national origin, or immigration status. … Xenophobia or other forms of discrimination can have no place at Loyola or our larger community.”