KANSAS CITY, Mo. (AP) — Authorities say 1-year-old twins have died in a house fire in Kansas City.

Deputy Fire Chief Jimmy Walker says smoke was billowing out of the home when crews responded Thursday afternoon. The Kansas City Star reports that several people escaped the home, where four adults and six children were living. They told firefighters there were still children inside.

Walker says firefighters rushed in to find the children, and put out the blaze in 5 to 10 minutes. They found the twins — a boy and girl — in the room where the fire started.

Walker says, “It’s especially hard during the holiday times.”

The cause of the fire is under investigation. The names of the twins weren’t immediately released.