At least two children were killed and multiple others were injured in a house fire Friday morning in New York City’s Staten Island borough, officials said.

Firefighters received a call about a blaze in the Stapleton neighborhood of Staten Island at about 10:18 a.m. ET and arrived on the scene minutes later, where they faced “heavy, advanced fire on the second floor,” said Jim Long, a spokesperson for the Fire Department of New York.

A 5-year-old girl was pronounced dead on the scene, while a 6-year-old died at the hospital, according to the New York Police Department.

At least two other children were injured in the fire, authorities said.

It was unclear what the relationship was between the victims, but Long said authorities believe they were all from one family.

Other details, including what may have caused the fire, were not immediately available.

This is a developing story. Please check back for updates.