German union Verdi has called a fresh three-day strike at five Amazon warehouses, increasing pressure on the online retailer during the busy pre-Christmas period in a long-running dispute over pay and conditions. Verdi said in a statement it had called on workers to strike at distribution centres in Bad Hersfeld, Leipzig, Graben, Rheinberg and Werne. The walkouts are to start during the night shift running from Sunday to Monday and will run until the end of Wednesday's late shift, Verdi said. Verdi wants Amazon to raise pay for workers at its distribution centres in accordance with collective bargaining agreements across Germany's mail order and retail industry and has organised several stoppages since early 2013. The U.S. company employs almost 10,000 warehouse staff at nine distribution centres in Germany, its second-biggest market behind the United States, plus more than 10,000 seasonal workers.   "Amazon categorically refuses to recognise employees' right to a collective agreement and sees unions as unnecessary," Verdi executive Stefanie Nutzenberger said, adding the company could end the strikes by entering into a collective deal. Amazon, which could not immediately be reached for comment on Friday on the latest strike call, has so far rejected the union's demands, arguing it regards warehouse staff as logistics workers and says they receive above-average pay by the standards of that industry. (Reuters)