DETROIT (WWJ) - Five young children and a firefighter have been injured in a house fire in northwest Detroit.

The fire broke out at around 9 a.m. Thursday, on Pembroke near Lahser Rd., and was out before 10 a.m., according to Deputy Detroit Fire Commissioner Dave Fornell.

Fornell earlier said it was believed the kids had been left home alone. However, authorities later learned that the mother of some of the children and her boyfriend were in the house, but were sleeping.

"The fire was contained basically to a mattress in one of the children's bedroom. And at this particular point we don't know if the children were playing with lighters, or if it might have been a space heater," Fornell said.

Fornell said the kids -- a 4-month-old girl, two 2-year-old girls, a 3-year-old boy and a 4-year-old girl -- all suffered from smoke inhalation. CPR was being performed on at least one of the children, he said, and all of them were taken to Children's Hospital for treatment.

"They have the 4-month-old in an incubator; another child intubated," WWJ's Mike Campbell reported.

All of the children, from two families who live in the home, were listed in stable conditions later in the morning.

A firefighter hurt while trying to kick in the door was also taken to a hospital, Fornell said, but he is expected to be OK. The adults in the home were not injured.

While the home doesn't appear to have been too severely damage, neighbor Asia Tucker said it was a startling scene.

"I just came outside, and they just kept yelling," Tucker said. "They just kept trying to get Tyler to wake up; they just kept screaming, 'Wake up, wake up, wake up!' and I kept seeing the smoke coming out the door."

An investigation is ongoing.