Police say multiple charges are pending against two brothers in connection with a sexual assault Friday involving a 17-year-old girl.

Calgary police Sgt. Melanie Oncescu said the teen was assaulted first in a back alley and then later at a house in a nearby community. (CBC)

In a press conference Sunday afternoon, Sgt. Melanie Oncescu with the Calgary Police Service said charges of abduction, forcible confinement, sexual assault and assault are expected to be laid.

Police say the 17-year-old was approached by two men while waiting for a bus around 11:30 p.m. MT.

They then dragged the girl into an alley and sexually assaulted her.

After that, police say she was walked from the bus stop at Taradale Drive and Tara Cove Road to a neighbouring community.

"I will stress that the victim was not impaired when this took place. However she was forcibly taken from the one address to the other, which would potentially have somebody who may have seen this perhaps thinking she was impaired and needed assistance in walking," Oncescu said.

She was then held overnight in a home and repeatedly sexually assaulted, she said.

The victim may have suffered a concussion, they said.

She managed to escape the house around 8 a.m. MT while police say the men were distracted and then fled to her family, who brought her to police.

On Sunday morning, three men — two brothers and their father — were taken from the house into custody but police say only the brothers were held.

Since no charges have been laid, police are not naming the men in custody.

Police are looking for any witnesses who may have seen the girl accompanied by two men.