From the BBC News summary for the attack, two of six points:
  1. German police are questioning a suspect, believed to be a Pakistani migrant
  2. The arrested man denies involvement and police say it is not clear he was the driver
  3. German Chancellor Angela Merkel has said it is a terrorist attack
  4. Mrs Merkel said Germans would find the strength to live 'free and open lives'
Link to the running update:http://www.bbc.co.uk/news/live/world-europe-38370364

Thanks to our local member, Outlaw 09, who has given the reported details and context.