Updated

A fire tore through an orphanage in Bosnia's capital Sunday, killing five children and injuring at least 18, police and hospital officials said.

The fire at the Ljubica Ivezic orphanage in downtown Sarajevo started around 6 a.m., said police spokesman Dragan Furtula.

The blaze broke out on the third floor of the building and rapidly spread to three rooms where younger children were sleeping, according to the Sarajevo fire brigade.

Firefighters said the flames raced through the building so quickly that even though they extinguished the blaze in around 10 minutes they were not fast enough to save all of the children.

Firefighters rescued 23 children from the three rooms.

The injured were all children except for one, a nurse who was working at the orphanage. Several of the injured were in serious condition.

"All the children we hospitalized are babies," said Biljana Jandric, a spokeswoman for Sarajevo Kosevo hospital. "One baby was dead on arrival and for the other four (victims) everything was done but we could not save them. Seventeen other babies and a nurse are also hospitalized."

Authorities do not know what caused the fire, and an investigation has begun, the police spokesman said.