By Denis Balibouse and Philip Blenkinsop

SIERRE, Switzerland/HEVERLEE, Belgium, - A bus carrying a Belgian school party home from a ski trip crashed into the wall of a tunnel in Switzerland late on Tuesday, killing 28 people, including 22 children.

The bus, transporting 52 people, mostly school children aged about 12 from the towns of Lommel and Heverlee in Belgium's Dutch-speaking Flanders region, crashed in the Swiss canton of Valais, police told a news conference early on Wednesday.

A police photograph showed the bus rammed up against the side of the tunnel, the front ripped open, broken glass and debris strewn on the road and rescue workers climbing in through side windows.

"It is a sad day for all of Belgium," Belgian Prime Minister Elio Di Rupo said in a statement expressing his "great horror". He said he would travel to Switzerland on Wednesday.

The bus was returning to Belgium from a skiing holiday camp in Val d'Anniviers, a resort in the Valais Alps that border France.

Police said the bus had just joined the highway towards the Swiss town of Sierre after coming down into a valley. After travelling 2 km (1.2 miles) on the road, the bus bumped into the curb and skidded into an emergency siding in the tunnel.

The front third of the bus was completely torn apart. Many children were trapped in the wreck and had to be freed, said police.

About 200 police, firefighters, doctors and medics worked through the night, while 12 ambulances and eight helicopters took the injured to hospital.

NO WORDS, ONLY GRIEF

Children at St Lambertus school in the Belgian town of Heverlee were informed about the accident at an assembly before classes.

"We don't have words, only deep grief. They were supposed to be back now," Dirk De Gendt, the local priest who is on the school board, told Reuters.

Parents of the victims were due to meet at the school later in the morning and then travel by military plane to Switzerland.

"Some parents know their kids have survived. For others there is no news," said Belgian police spokesman Marc Vranckx.

The crash was the worst in Switzerland since 1982 when 39 German tourists were killed on a railway crossing when a train hit their bus. Twelve people were killed and 15 injured when a bus crashed into a ravine in the Valais region in 2005.

"In Valais, we have never seen an accident as serious as this," police spokesman Renato Kalbermatten said, adding the speed limit in the tunnel was 100 km per hour.

Last month, a British teacher was killed and more than 20 people hurt in northern France after a coach crashed while bringing schoolchildren home from a skiing trip in Italy.

Twenty-four other children aboard the Belgium-bound bus were injured and were being treated in hospital, police said. Two drivers on the bus were also killed. The cause of the accident was not yet known, police said.

Dutch news agency ANP cited the Belgian authorities as saying seven Dutch children were on the bus, but the Dutch foreign ministry could not immediately confirm the report.

Belgian Foreign Minister Didier Reynders told French radio Europe 1 the trip was organised by Belgian social organisations. The bus was one of three travelling together, and the other two had returned safely to Belgium, he added.

Switzerland's mountain regions have a history of deadly crashes. In 2001, a truck crashed in the Gotthard tunnel under the Alps, causing a blaze which killed 11 people. (Additional reporting by Katharina Bart in Zurich, Ben Deighton and Robert-Jan Bartunek in Brussels and Geert de Clercq in Paris; Writing by Emma Thomasson; Editing by Louise Ireland and Andrew Heavens)

Source: Reuters