A recent wave of computer attacks against big American banks is the work of Iran, mostly likely in retaliation for economic sanctions and online attacks fostered by the United States, according to security experts interviewed by The New York Times.

Government officials did not offer proof, but experts cited both the sophistication of the attacks and the fact the hackers sought disruption instead of theft, which would be a hallmark of state-sponsored attacks, The Times said.

“The scale, the scope and the effectiveness of these attacks have been unprecedented,” said Carl Herberger, vice president of security systems at Radware, a security firm hired by banks and cloud service providers.

Editor's Note: 'It’s Curtains for the US' — Hear Unapologetic Warning from Prophetic Economist.

“There have never been this many financial institutions under this much duress.”

Hackers have invaded the sites of big banks including Bank of America, Citigroup, Wells Fargo, U.S. Bancorp, PNC, CapitalOne, Fifth Third Bank, BB&T and HSBC since last fall.

The attacks denied online banking service to customers, but no bank accounts were breached and no customer funds were stolen, The Times reported.

A hacker group calling itself Izz ad-Din al-Qassam Cyber Fighters claimed responsibility for the attacks, purportedly in retaliation for the online posting of an anti-Islam video that mocked the Prophet Muhammad.

But American intelligence officials told The Times the group is really a cover for Iran and claim Iran is waging the attacks in response to Western economic sanctions and for a series of cyber attacks on its own systems.

In the last several years, three sophisticated computer viruses have hit computers in Iran. Various reports last year attributed Stuxnet, the virus used to destroy centrifuges in an Iranian nuclear facility in 2010, to the United States and Israel.

"It's a bit of a grudge match," James Lewis, a security expert at the Center for Strategic and International Studies in Washington, told The Times.

The Times of Israel last month reported on a new virus, dubbed “Batchwiper,” that targets high-priority computers in Iran and completely wipes out the data on disk drives.

Iranian officials blame U.S. and Israeli hackers for attacks on Christmas Day, which targeted computer systems at a power plant and other industries.

CNNMoney reported that some experts predict the cyberwar that is already under way will get hot this year — with real deaths.

"Nation-state attackers will target critical infrastructure networks such as power grids at unprecedented scale in 2013," warns Chiranjeev Bordoloi, CEO of security company Top Patch, according to CNNMoney. "These types of attacks could grow more sophisticated, and the slippery slope could lead to the loss of human life."

Editor's Note: 'It’s Curtains for the US' — Hear Unapologetic Warning from Prophetic Economist.