Workers went on strike at a German site of Amazon on Monday, aiming to hit the US online retail giant in the busy pre-Christmas season amid a long-running pay dispute.Services sector union Verdi said workers had walked out at midnight at one of the company's nine distribution centres in Germany, in the central city of Bad Hersfeld in Hesse state.Verdi said it wanted to "raise the pressure on Amazon in the Christmas sales season" while Amazon was offering a special discounts campaign and volume was up sharply.

The union wants Amazon to bring the pay of its some 9,000 workers in Germany in line with wages in the mail order and retail industry. Amazon has argued that its centres are logistics sites and that it pays its staff accordingly.Verdi will keep up the pressure in the dispute, now entering its second year, "as long as Amazon denies workers respect and protection through collective agreements", said the union's Stefanie Nutzenberger.