Yale, Harvard, Stanford and 14 other elite universities have joined the legal battle against President Donald Trump’s immigration order, filing an amicus brief in the U.S. District Court for the Eastern District of New York on Monday.

In the brief, the 17 universities emphasized the importance of international collaboration in higher education and highlighted the “serious and chilling implications” of the order for foreign students and scholars.

“The executive order divides students and their families, impedes universities’ ability to draw the finest international talent and inhibits the free exchange of ideas,” the University said in a statement on Monday. “The brief affirms the vital importance of American safety and security, but urges that this interest be addressed through a policy that does not inflict such great burdens on law-abiding individuals, to the significant detriment of American higher education.”

On Jan. 27, Trump signed an executive order suspending entry of all refugees to the U.S. for 120 days and blocking citizens of Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen from entering the country for 90 days.

After Trump signed the order, which caused detainments at airports and derailed refugees’ travel plans, a Yale Law School clinic worked alongside the American Civil Liberties Union and other organizations to force an initial stay of the immigration policy. On Jan. 29, University President Peter Salovey expressed alarm at the executive order, writing to the campus community that “all of us are worried for colleagues, friends and family members who may be affected.”

Last week, the U.S. Court of Appeals for the 9th Circuit froze the implementation of Trump’s order nationwide, upholding a previous ruling by U.S. District Judge James Robart that blocked key parts of the travel ban.

According to the brief filed on Monday, more than 4,000 international students and scholars are affiliated with Yale, including 11 percent of the University’s undergraduate population and 10 percent of its faculty. Trump’s executive order has curtailed the academic research of the MacMillan Center Political Violence FieldLab and disrupted recruitment by the center’s Council on Middle East Studies, the brief states.

Abd al-Karim al-Iryani GRD ’68, the former Prime Minister of the Republic of Yemen, holds a Ph.D. from Yale.