US banks hit by more than a week of cyberattacks

LONDON (AP) - U.S. banks have been buffeted by more than week of powerful cyberattacks whose perpetrators remain unknown.

A series of American financial institutions have experienced disruptions after their sites were overwhelmed by unusually high amounts of traffic.

An expert whose company has analyzed some of the rogue traffic says that while the recent spate of cyberassaults weren't sophisticated they ranked among the largest he had ever seen.

Mike Smith, with Web security company Akamai, said Friday that the attacks delivered around three times the amount of traffic typically used by criminals to jam e-commerce websites.

Responsibility for online attacks is notoriously difficult to prove, but speculation has focused on an Internet posting suggesting that Islamists were taking revenge for an anti-Muslim film which has sparked violent protests across the Middle East.