(CNN)Five students at California State University, Long Beach tested positive for Covid-19, prompting a campus-wide quarantine.
All students living on-campus will be tested for the virus, and in-person classes have been canceled for the next two weeks, CSULB President Jane Close Conoley said in a letter to the university's community.
The decision comes after school officials learned that "a number of students who have not heeded our guidance related to COVID-19 precautions and congregated socially off campus earlier this month," Conoley said.
Five of those students have tested positive, Conoley said, and four of them live at the university's residence halls.
The quarantine will impact about 1,000 students who are living on campus for the fall semester and an estimated 3,000-4,000 students who attend in-person classes, according to the university's safety measures.
"As you know, we took a conservative approach to the fall semester by vastly reducing the number of students in our residence halls and the number of classes offered on campus," Conoley wrote. "Unfortunately, even with our proactive efforts we need to adapt and respond to this new challenge."
More than 40,000 cases of Covid-19 have been reported among students, faculty and staff at colleges and universities nationwide, according to a CNN tally from earlier this month.