International students have already been denied entry to the United States under new Trump administration rules that bar them from the country if their schools hold all classes online amid the coronavirus pandemic, according to a court document filed on Sunday. The “friend of the court” brief, written by dozens of universities and colleges, was filed in support of a lawsuit brought by Harvard University and the Massachusetts Institute of Technology (MIT) seeking to block immigration rules issued on July 6 that blindsided academic institutions across the country. The brief said US immigration authorities were “already preventing returning students from re-entering the country” and cited the case of a DePaul University student returning from South Korea who was denied at San Francisco International Airport. DePaul declined to make the student available for an interview. A US Customs and Border Protection spokesman did not comment about students being denied entry under the new rules. The brief was just one of a flurry of filings in support of the lawsuit from major business associations, labour unions and tech companies, including Google, Microsoft, Facebook and Twitter. They were joined by more than two dozen cities, towns and counties that decried the rule.