Three Toronto Police Service officers have been arrested and charged with sexual assault in an alleged attack on a woman in January.

The three are facing charges of sexual assault and gang sexual assault.

"These kinds of things are always disturbing," Toronto Mayor John Tory said Thursday.

"I hope that we don't see these kinds of things happening very often."

All three officers are attached to 51 Division and all were off duty at the time of the alleged offence.

The three officers are: Joshua Cabero, 28, with four years' service; Leslie Nyznik, 38, with five years' service; and Sameer Kara, 31, with six years' services.

Police allege that on Saturday, Jan. 17, 2015, they were involved in a sexual assault of a woman.

Toronto Police Association President Mike McCormack said the complainant is a female officer who works in the parking enforcement unit.

The police association unit said it would not be making any further comment until the complaint had been fully investigated.

Police Chief Bill Blair said he would also not be making any further comment on the investigation as the matter is before the courts.

He said the Toronto Police Service treats sexual assault investigations "very seriously for all victims of sex crimes."

He added that he believes police have taken "the appropriate steps to ensure that the support is provided to this individual and to other members of (the) service and members of the public who may have had a similar experience and require support."

The officers appeared in court on Thursday, and were released on bail.

All three officers have been suspended with pay, Toronto Police Communications Director Mark Pugash said. The victim will continue to receive a full range of support from the police service, he said.

Police will conduct an internal investigation after the court process is finished.

"I trust that the findings will end up in the hands of the public and we'll be able to see it dealt with that way," Tory said.