German intelligence services say they’ are taking seriously threats made by Islamist extremist groups as the country prepares to go the polls.One internet video, featuring a man claiming to represent the Taliban, warns of attacks against Germany if it does not withdraw its troops from Afghanistan. An apparent al Qaeda video making similar threats has also appeared on the web. Berlin has more than 4,000 soldiers in Afghanistan and their continued presence there is a big issue in the campaign. The latest threatening message included images of Germany’s defence and interior ministers and a number of well-known German landmarks. Security has been stepped up across the country ahead of voting. Germany has not yet suffered a major attack by Islamic militants on home soil, but authorities say they have thwarted plots.