ORILLIA, ONT. -- Lakehead University security experts in Orillia are trying to solve a debilitating cyber-attack and get students and staff back online.

The information technology services team first noticed unusual activity on the network last Tuesday, which led to a system-wide shutdown.

"As you can imagine, in order to protect our systems and all of our data as much as possible, we removed all access to all of our systems," said Kathy Pozihun, Lakehead University vice president of administration and finance.

The university's website, email, and learning platforms were restored over the weekend, but the disruption prompted an extension to students' winter study period.

"We did make the decision to extend the winter study break by four days, and we will be resuming classes this Friday," said David Barnett, Lakehead provost and vice president (academic).

It's unclear what the nature of the cyber-attack was or whether any of the university's data was breached, but the university, plus provincial and federal authorities are investigating.

University officials said students and faculty would receive updates through the school's communication channels and social media platforms.