An advocacy group representing Canada’s university and college professors is strongly urging academic staff to avoid non-essential travel to the U.S. amid an “evolving political landscape.”

The Canadian Association of University Teachers (CAUT), a group of independent associations and trade unions that represent 72,000 teachers, researchers and other staff at 120 universities and colleges, issued its updated travel advice on Tuesday.

“CAUT strongly recommends that academic staff travel to the U.S. only if essential and necessary,” the warning reads.