Rescuers seek answers as Belgium mourns 22 children in horror crash

Coach hits kerb and collides head on with tunnel wall as it returns from school ski trip

Swiss prosecutors were last night conducting an examination of the wreckage of the Belgian coach, which ploughed head-on into an alpine tunnel wall late on Tuesday, killing 28 people, including 22 schoolchildren, in one of the worst bus accidents in the country's history.

The coach, belonging to Belgian travel company Top Tours, had a total of 52 people aboard when it hit the kerb in a modern, fully-lit, one-way tunnel near Sierre in the southern Swiss Alps at about 9pm. The vehicle then swung out of control and collided head on with a wall in an emergency stopping bay. Photographs of the badly mangled front of the coach showed the vehicle's sides smeared with blood. Rescue workers spoke of "shocking scenes" as they tried to extract dead and injured children trapped in the wreckage. Christian Varone, the Swiss police chief in charge, said it was "like a war". Police and prosecutors were trying to establish whether human error or mechanical failure had caused the accident. All the children on board were said to have been wearing seatbelts. "We have no theory as yet, the investigation is still continuing," Varone told a press conference yesterday.

Although eyewitnesses said the scope of the damage suggested the bus had exceeded the 62 mph speed limit in force in the tunnel, Swiss prosecutor Olivier Elsig said yesterday the bus was not speeding. Police claimed CCTV pictures of the bus suggested it had hit both sides of the tunnel.

Jean-Pierre Deslarzes, the officer heading the rescue, said: "The rescuers have seen scores of road accidents, but this one has left many of them traumatised."

The coach had been carrying pupils from different schools in the Belgian towns of Lommel and Heverlee. With an average age of 12, they were on their way back from a week's skiing holiday in Val d'Anniviers in the Valais Alps bordering France. One of the schoolgirls had written in a blog only days before that she found the trip "mega-cool".

Six adults accompanying the party, including teachers and two bus drivers, were killed in the crash. A further 24 pupils were injured, many of them seriously. More than 200 police, firemen and medical staff worked through Tuesday night at the scene. The injured were taken to hospitals in Lausanne, Bern and other cities. Three of the injured children were said to be in a critical condition last night.

News of the crash caused deep shock in Belgium, where distraught parents of the victims assembled at their children's schools yesterday to wait to be flown to Switzerland on military aircraft. "Some parents know their kids have survived, but for others there is no news," said Belgian police spokesman Marc Vranckx.

Belgium's Prime Minister, Elio Di Rupe, travelled to Switzerland with victims' relatives. He told journalists last night: "It is our duty to accompany these people who are going through so much pain."