Warning: The following story and video contains offensive and disturbing language.

York Region Transit is investigating after a bizarre tirade by a woman on a York region bus was caught on camera.

The footage shows the woman hurling various insults and obscenities at a fellow passenger — and has been viewed more than a million times since it was posted on Facebook on Saturday.

It's not entirely clear what led to the interaction between the woman and her fellow passenger, but the video, posted by Newmarket resident Jesse Smith, captures more than a minute of the woman berating someone who appears to be an older female rider. Smith could not be reached by CBC News on Sunday.

Woman called fellow passenger a 'dust fart' in video that's been viewed more than a million times. Source: Jesse Smith/Facebook 1:24

"You're a dust fart," the woman can be heard saying to the older passenger. "You senile psycho old toot."

At later points in the video, she also calls her "slutty" and a "weathered vagina."

Incident not reported to transit service, police

York Region Transit and York Regional Police are both aware of the video — but say no one has reported the incident directly.

Insp. Russ Bellman said police are at a "bit of a standstill." They hope to speak to people who were on the bus to get a better sense of what was going on.

"What happened before the video started running? What was the context? Are there mental health issues at play here?" he said. "These are questions we don't have the answers to, because no one has called us to fill in the blanks."

York Region Transit is investigating

The bus driver did report the incident to his supervisor, however.

Ann-Marie Carroll, general manager of York Region Transit, said a full investigation is happening, which includes pulling video from the bus cameras, speaking to the bus operator and collecting other information.

In the video, the driver appears to stay seated throughout the confrontation, but Carroll said he was "trying to coax the woman off the bus verbally."

If he had stood up, "it might have escalated into something more than it already is," she said.

'Get cancer,' woman says to fellow passenger

The video shows the woman eventually walking toward the front bus exit, at which point she coughs in the seated passenger's direction, then turns around to say: "I have SARS by the way. And AIDS. And herpes."

"Oh good, I hope so," the passenger replies.

When the woman reaches the front, she stops and asks the driver to have the other passenger — who is still seated — removed from the bus.

"You senile psycho old toot," a woman on a York Region bus said to a fellow passenger. It was caught on camera and has since been viewed more than a million times on Facebook. (Jesse Smith/Facebook)

"You might want to kick this one off, eh? She seems a little bit nuts. She's yelling at me when I'm on my phone call," the woman says to the driver.

The seated passenger tells the woman to "get off" the bus, and later reaches into her pocket.

"What, you're gonna call the cops?" the woman says. "Go the f--k ahead. My dad's a cop, b---h."

The woman accuses the other passenger of eavesdropping on her phone conversation and continues calling to her as she makes her way off the bus.

"Get cancer, b---h," the woman says.