Thousands of people have attended a memorial service in Belgium for the 22 children and six adults who were killed in an horrific coach crash in Switzerland.
Earlier, there were emotional scenes as the parents of the pupils who died in the tragedy visited the scene of the accident.
After visiting the morgue to identify the bodies of the 28 victims, relatives were driven from their hotel to the Swiss motorway tunnel near the town of Sierre to lay flowers.
Police have said they still do not know what caused the crash - but they are investigating reports the driver may have been helping a teacher change a DVD when the crash happened.
A service has been held in the small Belgian town of Lommel, where 17 of the victims were from.
The town's grief has set the tone for a national day of mourning on Friday, when a minute's silence will be observed at 11am (local time).
"The whole country weeps for its children," Prime Minister Elio Di Rupo told parliament.
Flags will fly at half-mast and drivers of buses, metros and trains throughout the country have been asked to switch off their engines as a mark of respect.
Forty-six children and four teachers from two Belgian schools were returning home from a skiing holiday on Tuesday when their coach slammed into a tunnel wall in southern Switzerland.
The first of the 24 children who were injured in the crash headed home on Thursday evening, while the bodies of the dead are due back in Belgium on Friday.
Two military C-130 transport aircrafts will be used for the repatriation.
Swiss police spokesman Jean-Marie Bornet said authorities were working to release the bodies of all the victims as soon as possible.
The bus driver's body will remain in Switzerland while a post-mortem is carried out to determine if he was suffering from a medical condition that could have caused the accident.
Investigators are still trying to explain why the modern, well-equipped coach suddenly veered to the right as it drove through the 2.5km-long tunnel, and smashed into an emergency layby.
Swiss and Belgian media reports said survivors of the crash have suggested the driver had reached to help change a DVD on the entertainment system shortly before the crash.
According to the Swiss prosecutor, the coach was not exceeding the 100km-per-hour speed limit and authorities believe the 52 passengers on board the vehicle were wearing seatbelts.
Investigators are also studying CCTV images from cameras fitted in the motorway tunnel.
A doctor treating some of the young survivors has told Sky News they have been asking about the fate of their school friends.
Dr Michael Canans, who works at the hospital in Sion where 14 children were admitted on Tuesday night, said most of them have fractures of the lower limbs.
But he admitted that the psychological damage could be severe.
"Of course, this is very important and we have a team of psychologists who are also here and in the other hospitals, and with the parents," he said.
"Slowly, they understand that a lot of their friends did not survive so it's a very traumatic event, of course.
"They talk, and they ask, but at the moment we are not 100% sure who survived and who did not."
The parties from two schools in northeast Belgium had been on their way home from a skiing trip in Val d'Anniviers . Those killed include 21 Belgians and seven Dutch nationals.
The bus was travelling on the A9 towards Sion, in the Valais region, when it suddenly swerved to the right, struck a kerb and hit the motorway tunnel.
The impact of the smash was so severe that many passengers were trapped in the wreckage and had to be freed by emergency workers.
The crash has been described as one of the worst traffic accidents in Swiss history.