GENEVA (AP) — Relatives of the 28 people killed when a bus from Belgium crashed inside a Swiss tunnel faced a heartbreaking task Thursday: identifying the bodies ahead of their repatriation. Most of the dead were children.

Family members, some sobbing, were driven from a hotel in the southern Swiss town of Sion to the nearby morgue, where the bodies of some of the 22 schoolchildren and six adults killed in Tuesday’s crash were being kept.

“Where possible, the bodies will be shown to the families,” police spokesman Jean-Marie Bornet told The Associated Press. “In some cases this is not possible because the bodies are too badly injured.”

Afterward, relatives visited the site of the crash inside the Tunnel de Geronde near the Swiss town of Sierre. An AP reporter saw family members carrying flowers to the site where 21 Belgians and seven Dutch were killed.

The tourist bus carrying 52 people hit a wall Tuesday night less than an hour after heading home from a ski vacation in the Swiss Alps. Twenty-four other children were hurt, some seriously.

Bornet said authorities were working to release the bodies of all the victims as soon as possible. Some still had to be identified.

In Belgium, plans were being made to begin repatriating the bodies with military planes as early as Thursday evening, and authorities announced that Friday would be a national day of mourning.

In Sion, Dr. Michael Callens said Thursday that the 14 children in the city’s hospital were “doing well” and should be able to be repatriated to Belgium soon.