SAN FRANCISCO -- A woman was plucked from the third-story window of a burning San Francisco apartment building early Monday as deadly flames and smoke from the two-alarm blaze closed in around her, authorities said.

San Francisco fire spokeswoman Mindy Talmadge said the fire was reported around 6:40 a.m. at a three-story residential building at 18th and Market streets.

Arriving firefighters discovered that the advancing flames had trapped a female resident in the front of the building in a third-floor bay window. They quickly rescued her using a ladder,

"There was an individual trapped in the third-story bedroom," Talmadge said. "They were able to remove the trapped individual.”

Another resident told KTVU that the flames spread very quickly.

“When I looked on the side of the house the flames were shooting straight up,” she said. “It happened so quickly.”

The rescued woman was not injured, but another resident suffered from smoke inhalation after he raced back into the burning building to rescue a cat.

Arson investigators had traced the origin of the blaze to a backroom, but had yet to determine how it started.