DENVER -- Five people in a Denver high-rise were rescued after fire broke out in a hallway Wednesday afternoon.

The fire started on the sixth floor of the William Tell Building, located at 1599 Williams, said Denver Fire Department spokesman Phil Champagne.

"(The fire) appears to have originated in the hallway, it was heavy fire involvement thus trapping occupants in their units," Champagne said.

When firefighters arrived, shortly after 4:45 p.m., flames were "heavy" on the sixth floor and thick smoke rose to floors above, Champagne said.

Two people were rescued from their balconies by firefighters who used ladders and buckets to pluck them to safety. One person was taken from the sixth floor the other was on the seventh.

Champagne said five people were evaluated at the scene. One person was transported to the hospital for smoke inhalation.

Their ages and identities are not known.

"All of a sudden the fire alarm went off, there was smoke everywhere; I opened my door and smoke came in," said Jack McCaslin, a resident of the 10th floor.

Judy Brooks also lives on the 10th floor. She told 7NEWS she thought, at first, it was a false alarm. She soon saw smoke filling her apartment.

"This was serious," Brooks said, and added that she and her small dog then walked down 10 flights of stairs to safety.

The cause of the fire is under investigation.

The 81-unit building has 10 stories and a sign outside said it caters to "senior living."

The Red Cross said nine elderly residents and three pets were displaced by the fire. Volunteers are helping assist them with temporary housing.

A spokeswoman for the property management company, Monroe, said 8 people were in hotels Wednesday night, and managers would cooperate fully with investigators charged with determining how the fire started.

7NEWS Reporter Lane Lyon contributed to this report.