Fire spread through an apartment building early Tuesday, killing four children as firefighters already in the neighborhood rushed to the scene.

Two people were hanging out of second- and third-story windows when firefighters dealing with a car fire spotted smoke coming from a building down the street, Assistant Fire Chief Mike Darnell said. They had to call in a ladder truck to reach the building's top floor, where the children were found.

The young victims were siblings: a 7-year-old girl, twin 5-year-old boys and a 3-year-old, said fire department spokesman Larry Gray.

"They were probably asleep," Gray said.

Eight people were in the building at the time of the fire. Three adults, including the children's mother, and an infant were taken to a nearby hospital, Gray said. He did not know their conditions.

The cause of the fire wasn't immediately clear, but arson investigators could be seen through the broken windows. Gray said the fire appeared to have started on the second floor, where there were apartments.

Firefighters found the four young victims together in a bedroom after rescuing their father from a third-floor window, Darnell said.

A sign posted in a street-level restaurant window in the building read: "Closed today due 2 our loss."

Kevin Eubanks, a neighbor who manages the downstairs restaurant, said he woke up around 4:30 a.m. to the sound of screaming. When he saw the smoke, he ran outside and broke open a chain-link fence gate so people in the burning building could escape down an alley.

"I was yelling upstairs to the people, 'Get out of there!"' Eubanks said.

Heavy smoke was pouring from a third-floor window, he said.

"One guy was hanging out the window on the front trying to jump down," Eubanks said. "A fireman put him on his back."

Eubanks said he had often seen the children running around the building.

"They were good kids. Beautiful children. It's just tragic," he said.

The neighborhood, a mix of dilapidated buildings and some new construction, has several older homes.