One woman was killed and a child was hospitalized after a fire at an apartment building in Chester, Pennsylvania, on Thursday morning, officials said.

Crews were called to the building on the 1400 block of Congress Street around 8 a.m. and fought a fire on the second floor, Fire Commissioner John Paul Shirley said at the scene.

Shirley said there were five people trapped on the floor but three were able to get out on their own. Shirley said some people jumped from the second floor to escape.

One of the people who jumped, an adult woman, suffered life-threatening injuries from the fall, Chester Mayor Stefan Roots' office said in a news release. Police performed CPR on the woman after she jumped, but she died from her injuries at Crozer-Chester Medical Center, Roots said in a release. 

Shirley identified the victim as Jennifer Patterson. Family members said she was 36 years old and a mother of three.

"I'm really at a loss of what to say because my head is all over the place," Terry Newsome, the father of Patterson's 4-year-old daughter, said.

Carole D. Morgan, Patterson's neighbor, heard the commotion.

"Terrible flames, all burnt out, smoke and everything," Morgan said. "Terrible, terrible situation today."

A second alarm was declared due to the number of victims, Shirley said.

Firefighters placed the scene under control in about 15 minutes.

The child was hospitalized at AI DuPont/Nemours Children's Hospital with injuries that were not life-threatening.

Multiple agencies were on the scene investigating how the fire started.

"We are heartbroken that the fire this morning has ended in tragedy, and our thoughts and prayers are with the family of the deceased," Roots said in a statement.

Earlier Thursday at the scene, Roots praised the quick response of the fire department and other residents.

"Neighbors came out to help almost immediately," Roots said. "They even told me the fire department came, just as they should have, almost immediately."

The response came at the fire department's shift change, but both shifts were on the scene, Roots added.

Damage was confined to one unit of the complex.

"This apartment complex ... could have easily spread and gone up in flames if they were arriving just five minutes later, so the response from the fire department is epic," Roots said.