House Fire Kills 6 Children of Congressman's Aide: 'An Unimaginable Tragedy'

The inferno ripped through a three-story home, killing six of nine children inside.

Six children, ranging in age from 9 months to 11 years, perished in a massive house fire in Baltimore Thursday.

The fast-moving inferno collapsed the home’s second and third floors as mother Katie Malone managed to stagger outside, led by an 8-year-daughter, who had rounded up two little brothers, ages 4 and 5.

Read: 911 Dispatcher Takes Call About House Fire From Her Own Daughter

Malone, who had nine children, is an aide to Maryland’s Democratic Rep. Elijah E. Cummings.

Her husband was at work when the house was engulfed in flames at about 12:30 a.m., according to Baltimore City Fire Chief Niles Ford.

Malone’s boss held an emotional press conference Thursday. “Sadly, six of her nine children perished. It’s a very difficult time for our office,” Cummings said.

She joined the congressman’s office 11 years ago and her duties included immigration and military issues. “My staff is a family and this unimaginable tragedy is shocking and heartbreaking to us all,” Cummings said.

Malone and her two surviving sons were listed in critical condition. The 8-year-old girl was in good condition and was expected to be released from a hospital late Thursday.

The dead children were a 9-month-old boy, a 2-year-old boy, 3-year-old twin girls, and two girls ages 10 and 11.

The cause of the fire is under investigation.

Read: Firefighters rescue 34 Dogs From Burning Home: 'It Was an Endless Chain of Dogs'

The fire was so intense it partially melted a car parked on the street, Baltimore Mayor Catherine Pugh told reporters.

Neighbor Robert Spencer, 51, came running when he saw the flames and heard glass breaking.

He stumbled into Malone and gave her his jacket, he told The Baltimore Sun.  "I was so emotional," the man said. "I said, 'Where’s the babies at? She said, 'They’re in the house.'"

Spencer tried to fight his way inside, but family members held him back. He went home and tried to sleep, he said, but he kept hearing the children's screams inside his head. "I cried all night," he told the paper.

Amy Stratton, a colleague in Cummings’ office, praised the mom in a Facebook post. “Kate Ward Malone is one of the best mothers I know on this planet!! Please, please pray for her & her family!!!! We need prayer warriors!”

A GoFundMe account established by a relative has raised more than $45,000.

Watch:  1- And 3-Year-Olds Killed in House Fire While Parents Were Out