A girl died in hospital raising the death toll in Sunday's school bus accident in southern Russia to five, the local police spokeswoman said.
"On Sunday night, a girl died in hospital, she was in a very grave condition," the spokeswoman said.
The accident occurred on Sunday afternoon when a musical school bus carrying 22 passengers, including 18 children, to a local music festival collided with another bus during the overtaking maneuvre and overturned on the Pyatigorsk-Yessentuki highway, falling into a five-meter ditch.
The spokeswoman said all the children had their seat belts fastened but she said the organizers of the trip had failed to inform police and therefore the school bus was not escorted properly.
Four people died straight away - two children and two women. Another 15 children and two adults, a teacher and the driver, are now in the hospital of Pyatigorsk.
A group of doctors from Moscow are flying in for assistance, and some of the patients might be transferred to Moscow hospitals.
Other participants in the music festival, Children of the Caucasus, paid a minute of silence to the victims and dispersed canceling the event, Russian children's rights ombudsman Pavel Astakhov said.
According to statistics, 30,000 people lose their lives in traffic accidents every year in Russia due to the poor state of highway networks and reckless driving.
