Three people were reportedly engaging in some sort of "sexual activity" on a Toronto streetcar on Thursday evening.

A 504 King streetcar was forced to stop at a busy downtown intersection during rush hour when two men and a woman were caught engaging in inappropriate activity as the vehicle made its way through the downtown core.

Witnesses said three unidentified people were "getting to know each other" at the back of a westbound car at about 5:30 p.m., TTC spokesman Brad Ross told media.

"The couple was engaged in some sort of sexual activity. I don't know to what degree," Ross said, adding that he could not confirm what exactly happened.

He said that this type of complaint is rare, but there are some people who "can't wait to get home."

Ross said the driver was forced to stop the car in the area of King Street and University Avenue, one of the route's busiest stops.

The streetcar was stopped for approximately 20 minutes waiting for police to arrive. A second streetcar was also affected by the delay as the first car blocked the tracks, according to riders who took to Twitter to vent their frustration.

The threesome fled the area before police arrived, and none of them have been arrested.

Police would not confirm witness reports that they were intoxicated at the time, and said Friday afternoon that they would not be investigating the incident.

Ross joked about the incident, saying that "every streetcar in Toronto is named desire," but he told The Canadian Press that sexual acts are not permitted on Toronto transit vehicles.

"People from all walks of life ride the system, including children, and we would ask that people who are using the system who wish to get to know one another a little bit better do so in the privacy of their own home or somewhere other than on a streetcar."

The incident inspired several jokes on social media: