The General Secretary of the World Council of Churches has written to faith communities in Belgium to express his sympathy after 28 people died in a coach crash in Switzerland.

The coach was carrying teachers and schoolchildren back to Lommel and Heverlee, in Belgium, at the end of a ski trip when it veered into the side of a tunnel on the A9 near Sierre.

The victims included 22 children, among them 11-year-old British boy Sebastian Bowles, who was a pupil at St Lambertus School in Heverlee.

The Rev Dr Olav Fykse Tveit extended his "heart-felt sympathy" and the "assurance that our thoughts and prayers are with all those affected by this tragedy".

"Words alone are inadequate to express our sorrow on hearing of Tuesday evening’s coach crash in Sierre, Switzerland with the loss of many precious lives, and so we place our trust in the Holy Spirit to pray in our prayers, to begin the process of alleviating human pain, and to aid us in our witness and service to those who grieve most deeply," he said.

Belgium is holding a day of national mourning to remember the victims of the tragedy. A minute's silence was observed today at 10:00 GMT and flags are flying at half mast across the country.

The bodies are being flown back to Belgium today on military aircraft.

Dr Tveit said "whole communities" would be crucial to the recovery of individuals and families.

After such a tragedy, he added that the "support we offer one another in faith is crucial to building the future".