The outage suffered by Amazon.com's European websites was due to a hardware failure but not due to hacking attacks, according to the company. The websites Amazon.co.uk, amazon.de, amazon.fr and amazon.es were down for almost half an hour late on Sunday night. Hackers have not made any claims of the attack so far.

The brief interruption to our European retail sites earlier today was due to hardware failure in our European datacenter network and not the result of a DDOS attempt, a spokeswoman for Amazon told Reuters.

The company came under huge criticism after it ousted the servers of whistle-blower site Wikileaks. 'Anonymous' hackers group vowed to bring down websites of organization that severed ties with Julain's Assange enterprise. DDoS attacks, which were part of 'Operation Payback', on websites of credit-card giants MasterCard and Visa last week, brought down the sites temporarily.

Officials from US administration earlier urged organizations to sever ties with Wikileaks for releasing confidential US diplomatic cables. Amazon however denied pressure from the US government.

Over the weekend, 'Anonymous' activists also announced that the group would primararily focus on 'publishing parts of the confidential U.S. diplomatic cables as widely as possible' rather than launching fresh cyber attacks.