By Mike Dougherty

PHILADELPHIA (CBS) – Two children were seriously injured in a house fire that broke out Thursday night in the Olney section of Philadelphia.

Officials say crews were called to the 300 block of East Sheldon Street around 9:45 p.m. and saw heavy smoke from the second floor when they got there.

They were able to quickly put out the fire.

Fire commissioner Adam Thiel says first responders were there within five minutes and they found two kids on the second floor.

“Both children were in critical condition when they were transported. One to Einstein one to St. Christopher’s, they remain in critical condition but they are improving.”

Thiel says the cause of the blaze is under investigation.