At least six children were killed and several others injured in a school bus crash in Chattanooga, Tennessee, the U.S.. The bus, carrying 35 schoolchildren aged five to ten, crashed on Monday afternoon, BBC reported.

It was noted that five children were found dead on board the bus after the crash, and another child had died in hospital. Chattanooga Fire Department also said 23 children had been taken to hospital by ambulance.

“Speed is being investigated very very strongly as a factor in this crash,” said Chattanooga police chief Fred Fletcher.

Investigators believe the bus may have hit a utility pole before colliding with the tree. The driver, who survived the crash, was being questioned and was co-operating with investigators.