A bus crashed into a truck in icy conditions Friday in southern Finland, killing 23 people and injuring 15 in one of the worst accidents in the country's history, officials said.

Thirty-six passengers ? most of them teenagers ? were on the chartered bus at the time of the accident, traveling to ski resorts in Lapland , northern Finland, he said. Most of the passengers were from the capital, Helsinki, or Finland's second city, Tampere.

Researchers were able to determine the precise angle and point of impact between the bus and the trailer carrying heavy reels of paper within 24 hours of the crash. The appallingly high death toll in the accident was caused in great measure by the shifting of several of the 700-kilogram paper reels in the trailer, which flew through the windscreen of the bus, killing most of the victims instantly.