Harvard University has told all students to move out of their dorms by Sunday, is canceling classes on campus and moving all courses online to try to "de-densify" the campus and limit any spread of the new coronavirus.

"The decision to move to virtual instruction was not made lightly," university President Lawrence S. Bacow said in a letter to students and staff that was posted online Tuesday. "The goal of these changes is to minimize the need to gather in large groups and spend prolonged time in close proximity with each other in spaces such as classrooms, dining halls, and residential buildings."

The school is transitioning to online instruction for graduate and undergraduate students with plans to offer all classes online by March 23, he said. Harvard is also limiting nonessential meetings to no more than 25 people, he said.

Harvard's spring break starts Saturday and ends March 22, and its spring term ends in late April. The university said students shouldn't return to campus after the break.

A spokesperson for the university declined to comment beyond what was posted to the university's website.

Students who can't afford transportation home are currently being referred to Harvard's financial aid office, according to its website. The university is also instructing students to speak with their dean if they have no place to go.

On Monday, Princeton announced similar measures, telling students that classes would be taught online following spring break. As a precaution, Ohio State University President Michael Drake also told students on Monday that all instruction for its more than 68,000 students would take place online until the end of March, although none of the state's three confirmed cases are associated with the university.

Syracuse University followed suit on Tuesday, telling students it was moving all classes online beginning at the end of the day Friday through at least March 30, "given the rapid spread of coronavirus across New York state."

The University of Washington in Seattle told students last week it would temporarily move online and resume normal operations by the end of March, affecting nearly 50,000 students.

As of Tuesday morning, Massachusetts, where Harvard is located, had one confirmed case of COVID-19 and 40 presumptive cases, according to the state's department of public health. There are currently 249 people undergoing monitoring or under quarantine in the state.

The decision comes as COVID-19 has swept across the U.S., infecting at least 755 in the U.S. and killing at least 26 as of Tuesday morning, according to data compiled by Johns Hopkins University.