The driver of a bus that crashed in a Swiss tunnel, killing 22 children and six adults, was trying to put on a DVD, survivors said ahead of a day of mourning. Young survivors of the horrific accident told their parents the driver, who died in the crash, tried to insert a disc into a player as he drove in the 2-mile Sierre tunnel seconds before the bus hit a curb, sped across a hard shoulder and went straight into a concrete wall, the Dutch-language Belgian daily Het Laatste Nieuws and the Swiss daily Aargauer Zeitung reported. A \"moment of distraction\" could have led to \"the driver losing control,\" the Belgian newspaper said. Fifty-two schoolchildren and staff from Belgium and Holland were returning home Tuesday night after a weeklong trip to the Alpine ski resort of val d\'Anniviers. Most of the children were 11 and 12 years old. Of the 24 who survived, some were still in critical condition Friday, officials said. Eight schoolchildren who survived were flown in Belgian military planes to Melsbroek Air Base at Brussels Airport early Friday. The bodies of the Belgian victims were to be flown back aboard a C-130 military transport plane later in the day, Belgium\'s Interior Ministry said. A ministry spokeswoman said there would be \"no communication\" about the landing \"out of respect for the victims and in agreement with the Swiss authorities.\" Local police spokesman Renato Kalbermatten confirmed the DVD theory was being examined, but he said it was speculation so far and closed-circuit TV from inside the tunnel \"did not make the situation very clear.\" The DVD theory was rejected by the driver\'s employer, the British broadcaster Sky News reported. Prosecutor Olivier Elsig ruled out speeding as a possible cause. An autopsy on the driver showed he was not affected by alcohol. Belgium declared Friday a national day of mourning, with a moment of silence observed around the country at 11 a.m. local time (6 a.m. EDT) and flags flown at half-staff. Dutch Prime Minister Mark Rutte ordered Dutch flags on public buildings flown at half-staff Friday. Six Dutch children were killed in the crash and a four were injured. The victims came from two Catholic elementary schools in Belgium, including one near the Dutch border. A German and a Polish national were also among the injured, officials said.