Relatives of the 22 school children and six adults who died in a coach crash on Wednesday have visited the site where their family members were killed.
According to reports parents wept as they paid their respects at the scene where their children died.
Photos also show tributes and flowers being left at the morgue where the children's bodies are being held.
Twenty-eight people were killed when a coach carrying 52 passengers travelling back to Belgium after a skiing holiday crashed into a wall of a tunnel in Sierre, Switzerland.
The wreckage of the coach
Elio Di Rupo, the prime minister of Belgium declared a national day of mourning following the crash. He said it was a "tragic day" for the country. "Words are useless," he told national radio and TV networks. "This is a tragic day for all of Belgium."
The cause of the crash is still being investigated. The coach had only been on the road for around half an hour, and according to investigators, was not speeding.
Pictures of those who died in the accident
A mourner pays their respects
There has been some speculation that the driver was suffering from a medical condition and possibly had a heart attack. An autopsy is being carried out on his body to see if this could have caused the crash.
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Valais police spokesman Jean-Marie Bornet said 52 people were on the bus carrying students home from a skiing trip crashed into the wall of a tunnel. A further 24 children were injured in the crash and taken to hospital.
The children are thought to have been from two different schools, the Sint Lambertus school in Heverlee and from the ‘t Stekske school in Lommel.
The wife of one of the drivers who died in the accident told Flemish television channel VTM on Thursday that she had learned about her husband’s death on the Internet.
After learning about the tragedy on an information website, she “called the coach company directly.”
Another Swiss newspaper, Le Matin, gave the account of a night guard who entered into the tunnel after the accident.
“I saw the front seats of the bus smashed one against the other; there was blood everywhere, and I could see the children who were still alive fidgeting so that someone could save them,” she said.
“No one was there. No policemen, no firemen. I realised there was nothing I could do alone so I called the rescue teams.”
The mother-of-two said she could still see the children's faces: "I can still see all those faces looking at me, not knowing if they were dead or alive. It was horrible.”
At the hospital in Sion, a doctor told the Associated Foreign Press that the surviving children seemed “excessively calm.”
“After everything they have been through, it is incredible. They are demonstrating an incredible stoicism,” he added.