Toronto police say they have charged three men following a human trafficking investigation.

Police allege a man coerced an 18-year-old woman into the sex trade in November 2017 with threats against her and her family, then sexually assaulted her numerous times, using a gun to intimidate her.

Officers say the woman was eventually able to escape and contact police.

They say a 21-year-old Brampton, Ont., man is facing 18 charges, including sexual assault, sexual assault causing bodily harm, sexual assault with a weapon, procuring a person to provide sexual services, unauthorized possession of a firearm and forcible confinement.

A 19-year-old man also from Brampton faces five gun possession-related charges in connection with the same investigation.

Police say that while investigating the 18-year-old woman's case, they found that a 17-year-old girl had also been forcibly confined and sexually assaulted on November 23 by an associate of the 21-year-old Brampton man.

Officers say that associate, a 22-year-old man from Toronto, has been charged with assault, sexual assault, forcible confinement and failure to comply with probation.