FLAGSTAFF (AP) — Northern Arizona University cracked down on students who hadn't received mandatory COVID-19 testing by locking them out of their online classes, a move that prompted most to get into compliance.

University spokeswoman Kimberly Ott said about 25 students were notified early in the past week they wouldn't have continued access to the online instruction system because they didn't get tests or seek an exemption even after three email notifications and a phone call, the Arizona Daily Sun reported.

The system is used for all online materials, including the submission of assignments and exams.

By Wednesday, most of the students completed testing or provided exemption information to get back online, Ott said.

The university would reactivate the other students' accounts once they meet the requirements, Ott said.

Faculty members heard about the crackdown from distressed students who were unable to access their accounts, Faculty Senate President Gioia Woods said.

"We all agree that a culture of compliance is CRUCIAL to containing COVID-19, and it's critical we all — faculty, students, staff — comply with the call for random testing," Woods said in an email. "But to block students in the final week of the semester is harmful, especially for students most at risk. And to do so without letting faculty or department chairs know resulted in panic and confusion."

Ott said the university had told students there would be penalties for non-compliance with the COVID-19 mitigation strategies.

In other developments:

Arizona on Saturday reported 3,628 additional COVID-19 cases and 30 more deaths amid increasing hospitalizations.

Arizona has been experiencing a rise in cases, hospitalizations and deaths since late September and early October. Officials have cited business and school reopenings and public weariness with COVID-19 precautions.

With the additional cases and deaths reported Saturday, the state's totals rose to 295,334 cases and 6,457 deaths, according to the state's coronavirus dashboard.

Hospitalizations reached 1,916 as of Friday, with 435 of those patients in intensive care beds, for a total of 24,181 over the outbreak.

The number of reported infections is thought to be far higher because many people have not been tested, and studies suggest people can be infected with the virus without feeling sick.

For most people, the new coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death.