The University of Cambridge has suspended examinations and is urging all students to “return home now” in response to the coronavirus pandemic.
International students have been asked to make travel arrangements “as quickly as possible” as global restrictions take hold.
Vice-chancellor Stephen Toope said teaching will move online and staff will work from home from Friday.
“We are all facing an unprecedented crisis,” he said.
The university has 23,384 students, of whom more than 40% are students from 140 countries. The greatest number of international students are from China.
University libraries will close from 17:00 on Wednesday and all buildings will be shut from 17:00 on Friday.
Laboratories, including those involving research relating to Covid-19 or “in the immediate national interest”, will stay open, the statement said.
In a letter sent to the university’s 31 colleges, Jennifer Marchant, of the Cambridge University and College Union (UCU) raised “grave concerns at the way [the university is] handling evacuation of students”.
“We are extremely concerned that the invitation to leave the country at such short notice will dramatically affect the most economically and socially vulnerable members of the college community,” she said.
The UCU is calling for financial support for students and the extension of residential permits by six months for “those who may soon enter a legal limbo”.
Prof Toope added: “It may be months before we resume normal activity.
“We will need all the fortitude, resilience and generosity of our collegiate university community to get us through.
“I am confident that this crisis will bring out the best in all of us.”