U.S. Secretary of State Marco Rubio said the US has revoked at least 300 foreign students’ visas as part of President Donald Trump’s effort to clamp down on pro-Palestinian protesters on university campuses.

“Maybe more than 300 at this point,” he said while speaking to reporters on a visit to Guyana. “We do it every day, every time I find one of these lunatics.”

Rubio was asked to confirm how many student visas the administration had revoked in its crackdown on rhetoric at universities that it considers anti-Israeli.