The US government has charged several Iranian hackers with coordinating a campaign of cyber attacks on dozens of American banks and a dam in New York state from 2011 to 2013.

The US Justice Department on Thursday announced the indictment of seven Iranian hackers, which was filed in a federal court in New York City.

The indictment described the suspects as "experienced computer hackers" who live in Iran and may have been working on behalf of the Iranian government.

The move marks the first time the US government has charged individuals tied to a foreign government with attempting to disrupt critical infrastructure.

The charged hackers are accused of conspiracy to commit computer hacking while employed by two Iran-based private computer companies.

At a news conference announcing the charges, US Attorney General Loretta Lynch, the head of the Justice Department, said the accused hackers caused tens of millions of dollars in damages in their assault on US banks.

�These attacks were relentless, they were systematic, and they were widespread,� Lynch said.

At least 46 major financial institutions and financial sector companies were targeted, including JPMorgan Chase, Wells Fargo and American Express, according to the indictment.

AT&T, the second largest provider of mobile telephone and the largest provider of fixed telephone in the United States, was also targeted, the indictment says.

Separately, the US Treasury Department blacklisted two Iranian companies on Thursday for supporting Iran's ballistic missile program. The sanctions came after the Islamic Revolution Guards Corps (IRGC) successfully test-fired two more ballistic missiles on March 9.

The US hacking charges come on the heels of a recent report that the US had developed an �elaborate plan� for an extensive cyber attack against Iran in case the negotiations to reach a nuclear agreement failed.

Code-named Nitro Zeus, the cyber attack plan was designed as an �alternative� to target Iran's air defenses, communications systems and crucial�segments of its electrical power grid, the New York Timesreported in February.

In June 2010, it was revealed that the US and Israel carried out a cyber attack against Iran to sabotage the country�s civilian nuclear program.

In that attack, Iran�s nuclear facility in Natanz was the target of the Stuxnet virus in what has become the most serious case of state cyber-terrorism because of its complexity and sabotage of sensitive properties.

By Press TV