MADISON, Wis. (CBS) — The University of Wisconsin-Madison is switching to remote learning for at least two weeks and quarantining two residence halls amid a spike in COVID-19 cases on campus.

In a letter to the campus community, UW-Madison noted that it had taken extraordinary measures to prioritize health and safety on campus while facilitating some sort of in-person activity for the fall. The university also partnered with public health experts to develop a method of testing, isolating, and managing the virus.

When positive coronavirus tests began to rise, UW-Madison took additional action. The university said on Monday, it restricted undergraduates to essential activities only, and worked with public health authorities to support the quarantine of students in many fraternity and sorority houses while requiring testing for all who lived in those houses.

But the positive test rate has continued to spike, hitting 20 percent or greater for the past two days. The university said the numbers reflect a rapid rise in infections in students who live off campus, as well as in certain residence halls.

Thus, tougher actions had to be taken.

Effective Thursday, in-person graduate, undergraduate, and professional school instruction will be halted, and will resume remotely starting Monday. The remote learning period will go on for at least two weeks.

Clinical training will be allowed to continue, and all classes and sections that are already being offered remotely will go on as planned.

The university said its contact tracing had not revealed any coronavirus transmission that resulted from in-person instruction, but the decision comes out of an abundance of caution.

Undergraduate research work that can be accomplished remotely must be conducted that way beginning Thursday and continuing until Sept. 25. Graduate and post-doctoral research may continue.

Because of a high number of positive tests in the Sellery and Witte residence halls, students who live in those buildings must quarantine for two weeks beginning at 10 p.m. Wednesday. All residents of those dormitories who have not gotten a coronavirus test will need to get one on site Thursday or Friday.

Meanwhile, in-person study spaces will be closed, dining services will be carry-out only, and university recreation and wellbeing facilities will also be closed. All in-person gatherings – including social events and work gatherings of more than 10 people are also canceled.

Students are advised not to travel home during the two-week period so as to protect themselves, their families, and the community.

“I share the disappointment and frustration of students and employees who had hoped we might enjoy these first few weeks of the academic year together,” Chancellor Rebecca Blank wrote in the letter. “Before we started this semester, we knew that no plan would be risk-free in the current environment.”