Bloodied pupils lay on stretchers, while other children walked away dazed with their parents after a school bus crash that killed six on Monday in Tennessee.
Chattanooga police Chief Fred Fletcher said the crash was "every public safety professional's worst nightmare".
The bus was carrying 35 children from Woodmore Elementary, pupils in kindergarten through fifth grade, when it crashed about 3:30pm local time, turned on its side and wrapped around a tree.
According to reports the driver of the bus has now been charged in connection with the incident.
Mr Fletcher said police were interviewing the bus driver to find out what happened and told reporters later that investigators were looking at speed as a possible contributing factor. The bus was the only vehicle involved, he said.
He said 23 pupils were taken to hospital, but did not have information about the extent of injuries.
Media reported it took about two hours to get the last children off the bus.
Television stations reported that people queued up to donate blood and some donors were asked to make appointments for Tuesday.
Kirk Kelly, interim superintendent for Hamilton County schools, said classes would be held on Tuesday, with counsellors available for pupils and staff.
Hamilton County District Attorney Neal Pinkston told media outlets that five people died at the scene and one died in hospital.
Police will not identify the children who died, or their ages, until parents were notified.
"Our hearts go out, as well as the hearts of all these people behind me, to the families, the neighbourhood, the school, for all the people involved in this, we assure you we are doing everything we can," Mr Fletcher said.
At the state Capitol in Nashville, Governor Bill Haslam called the crash "a tragic event" and offered assistance.
"We're going to do everything we can to assist in any way," he said. "It's a sad situation any time there's a school bus with children involved, which there is in this case."