Concordia University is warning its 45,000 students to be wary after two female students were lured off campus through Instagram and attacked.

One of the women was sexually assaulted.

The attacks took place in September and December of last year and the women alerted police and the school recently, prompting Monday's warning.

"We were alerted to this last week. As soon as we became aware we moved as quickly as possible to inform students as broadly and as widely as we could," said Concordia spokesperson Mary-Jo Barr.

She said the University notified students and is "urging them to be extremely vigilant in their social media interactions, whether it's conversations, whether it's people approaching them for various invitations, we're just asking them to be super vigilant on all social media platforms."

The two women who came forward said they were assaulted after responding to ads for job opportunities that they spotted on social media. The school is giving few details and would not say what kind of jobs the women were applying for.

Montreal police are investigating the incidents, and said both women were drugged.

It is possible other women at Concordia or other schools were attacked, and police are hoping any other victims will come forward.

The university's deputy provost and vice-president of services said students should be especially careful about unsolicited professional development invitations.

Concordia is advising students who need assistance to contact the university's Sexual Assault Resource Centre at 514-848-2424, ext. 3353

They can also reach out to Campus Security at 514-848-3717, option 1.

“You can't ever really trust who you meet online unless you know for sure the connection you have with them,” said social media expert Alissa Sklar of Risk Within Reason, a consultancy project focused on teens, technology and risks.

She cautioned to be skeptical of any unsolicited invitations.

“If you're going to set up a meeting with them, I would insist it happen in a public place, I think that anyone is going to be respectful of that, if it's a large office building or somewhere clearly an office a place of business, that's fine, but a lot of startups are started up in someone's apartment and you can't always be sure that is okay,” she said.