Secretary of State Marco Rubio has said his agency has the right to revoke the visas of foreign-born students he called “lunatics.”

Dallas-area international students are struggling to navigate why they were told to leave the country immediately after visas were suddenly revoked by federal officials, lawyers working with some of them said.

Students from University of North Texas, UT-Dallas, Texas A&M, UT-Rio Grande, Texas Woman’s University, Texas Tech and other schools have been affected.