Amazon.com Inc's (NASDAQ:AMZN) Web sites in Europe suffered an outage for more than half an hour on Sunday night, in what the company said was a hardware failure in its European data center network.
"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.
Amazon was among the first U.S. firms to pull the plug on WikiLeaks since it began publishing thousands of U.S. diplomatic cables, withdrawing hosting services last week after being questioned by the U.S. Senate Homeland Security Committee.
A loose grouping of activists operating under the name "Anonymous" had urged an online attack to crash the amazon.com site by overwhelming it with requests from users.
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.com's U.S. website was unaffected.
Amazon, which operates one of the world's biggest web-hosting businesses as well as a huge e-retail store, had no immediate comment.
The activists briefly brought down the sites of credit-card giants 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.