Amazon.com Inc's websites in Europe suffered an outage for more than half an hour on Sunday night due to a hardware failure in the company's European data center network. Amazon.co.uk, amazon.de, amazon.fr and amazon.es were all down for more than 30 minutes until around 2145 GMT when they appeared to work normally again.

Amazon rushed to explain the reason of the outage and said that it was a hardware failure in its European datacenter network and not the result of a DDOS attempt.

Amazon was recently hit by an online attack by activists operating under the name "Anonymous." The attacks followed Amazon's move to pull the plug on WikiLeaks since it began publishing thousands of U.S. diplomatic cables, withdrawing hosting services last week.

The activists had also brought down the sites of MasterCard and Visa which had stopped processing donations to WikiLeaks.

On Saturday, Anonymous said it had changed its strategy and would now focus on spreading snippets of the leaked cables far and wide rather than on cyber attacks.

Amazon operates one of the world's biggest web-hosting businesses as well as the popular and huge e-retail store.