Dalhousie University has issued a warning after four students reported they were served alcohol spiked with an unknown substance.

A security bulletin by the Halifax school Friday says the spiked drinks were allegedly served at an organized off-campus party.

“We got the email there was rumour of that going around, and actually the night of there was a rumour of a party that you shouldn't go to because people were spiking the drinks," said Dalhousie student Alia Hazineh.

The bulletin says students should pour their own drinks and not leave drinks unattended.

It urges students to intervene in instances of sexual violence by challenging the perpetrators and supporting the survivors.

The university isn't saying who organized the party or when it happened, but students are on alert.

"I was a little shocked to be honest that that would be happening so quickly in the school year," said Dalhousie student Stephanie Barrett.

"Personally and luckily no, I have not actually encountered any of that, and I hope I never do because it's pretty scary," said another Dalhousie student.

Dalhousie says there were no reports of assaults or injuries associated with the incident, and Halifax police say they haven't received any complaints either.

"It was taken as a precautionary measure to ensure that our students are aware of recent alleged incidents, and to ensure that they take appropriate steps/precautions if they find themselves in similar circumstances. Ensuring student safety is our highest priority, and we want our students to have important information to help them stay safe," said Dalhousie University in a statement to CTV News.

Police consider it a serious offence.

"Slipping a drug into someone’s drink for the purposes of sexual assault or any other reason is a pretty heinous crime and we want to know about it as soon as we can," said Staff Sgt. Andrew Matthews of Halifax Regional Police.

Dalhousie Security says if a student feels they have been drugged or sexually assaulted, they should seek medical attention or call a sexual assault response line.

For now, students seem to be satisfied with the school's response.

"Even though it didn't happen on campus, the fact that they’re looking out for their students is pretty good," said Stephanie Barrett.

With files from The Canadian Press and CTV Atlantic’s Allan April.