The New York City fire commissioner said on Monday that ambulances were dispatched later than they should have been to a Queens fire that killed two 4-year-old children and injured three other people late Saturday night.

Roughly eight minutes elapsed between the time firefighters confirmed the house was on fire and the time ambulances were called. Commissioner Salvatore J. Cassano said the cause of the delay — a delay noticed by frantic neighbors and firefighters — had yet to be determined by the Fire Department’s investigators.

“We’re listening to tapes, we’re looking at timelines and at the end of the investigation, we’ll see what actions need to be taken,” Mr. Cassano said at a news conference in Brooklyn.

The delay appeared to stem from a breakdown in communications between firefighters at the two-story home on Bay 30th Street in Far Rockaway and emergency medical service dispatchers, who must be alerted by their Fire Department counterparts before sending an ambulance to a reported fire.