Harvard University announced Thursday it is challenging the Trump administration’s ban on international students going there in court. President Donald Trump issued an executive order on Wednesday denying visas for foreign students aiming to study at Harvard.

President Donald Trump has escalated his standoff with Harvard University, seeking another path to prevent international students from attending the school after a judge blocked an attempt to revoke Harvard’s ability to enroll international students.

Harvard University sued to stop the Trump administration from barring its international students’ entrance to the US, adding to a high-stakes legal battle between the government and the school.