Firefighters rescued this 3-year-old girl — and her younger sibling — from their Brooklyn home Friday afternoon when a faulty air conditioner in another apartment went up in flames, filling the high rise with acrid smoke.

Richard Bryant Jr., whose father lives in the building at 272 Wyckoff St. in Boerum Hill, was walking home when he spotted his dad’s window air conditioner burning. He rushed inside, calling out to a neighbor to dial 911.

When he entered his father’s burning third floor apartment, it was “the worst thing I’ve ever seen in my life,’’ he said. He helped his father get safely out.

The children, who live on a lower floor, were taken to safety by the firefighters.

One of the youngsters suffered smoke inhalation and was taken to a local hospital.

Four other people sustained minor injuries.