The Dresdner Neueste Nachrichten paper said on Friday it had received one letter demanding an eight-digit euro amount of money within seven days and threatening that further attacks would be carried out if the money was not handed over.

The Dresdner Morgenpost said the threat was to Ikea stores in Hannover, Hildesheim, Bremen and Göttingen, but also suggested that detectives reckoned it could be from a fraudster who had no connection with the attack in Dresden. Other attacks have been carried out in Ikea stores in Belgium, France and the Netherlands in recent weeks.

Police investigating the explosion at the Dresden Ikea which slightly hurt two people last Friday evening, turned to television this week, making an appeal on the ZDF programme Aktenzeichen XY… ungelöst (Case File xy… Unsolved) which publicises unsolved crimes.

Following the show the state criminal police received 10 further clues to the case, but said nothing had emerged that looked decisive.

Hundreds of people were evacuated from the Ikea store in Kiel on Wednesday after a member of staff found a mobile phone wrapped in sheepskin abandoned in the bedroom section of the shop. Explosives experts were called to examine the phone, but gave the all clear two hours after the evacuation, and the people were allowed back in.

A number of Ikea stores now have private security guards posted at the doors, but it remains completely unclear what they might be looking out for.

DPA/The Local/hc