WASHINGTON (CBSNewYork/AP) — The U.S. Department of Justice on Thursday charged seven alleged Iranian hackers in a series of cyberattacks against banks and a small Westchester County dam.

Those charged are experienced hackers employed by computer security companies working on behalf of the Iranian government, including the Islamic Revolutionary Guard Corps, U.S. Attorney General Loretta Lynch said.

WEB EXTRA: Read The Indictment (pdf)

Hamid Firoozi, 34, is accused of gaining access to the control system of the Bowman Avenue Dam, a small flood-control structure in Rye Brook, about 20 miles north of New York City. Lynch said the dam was undergoing maintenance at the time of the alleged intrusion and had been disconnected from the system.

“But for that fact, that access would’ve given this defendant the ability to control water levels, to control flow rates — an outcome that clearly could’ve posed a clear and present danger to the public health and safety of Americans,” Lynch said.

As CBS2’s Sonia Rincon reported, it was still a mystery Thursday why the small Bowman Avenue dam tucked into the woods of Westchester County became the target of Iranian cybercriminals. But Lynch said it was one of 56 systems targeted in the U.S. – most of them banks.

Between 2011 and 2013, officials said Firoozi and six others allegedly carried out distributed denial of service (DDoS) attacks on dozens of banks, preventing customers from accessing their accounts online.

Customer information wasn’t compromised, but millions of dollars were lost when the systems were deliberately overwhelmed.

“Online services were disrupted. Hundreds of thousands of Americans were unable to access bank accounts online,” Lynch said. “These attacks were relentless, they were systematic and they were widespread. They threatened our economic well-being and our ability to compete in the global market place, both of which are directly linked to our national security.”

Though the individuals are not in American custody, officials said the goal is to put cybercriminals on notice that they cannot act with impunity.

“The FBI will find those behind cyber intrusions and hold them accountable — wherever they are, and whoever they are,” FBI Director James Comey said. “By calling out the individuals and nations who use cyberattacks to threaten American enterprise, as we have done in this indictment, we will change behavior.”

Firoozi and the other defendants — Ahmad Fathi, 37; Amin Shokohi, 25; Sadegh Ahmadzadegan, aka Nitr0jen26, 23; Omid Ghaffarinia, aka PLuS, 25; Sina Keissar, 25; and Nader Saedi, aka Turk Server, 26 — face conspiracy and other charges.

Only Firoozi is believed to have been behind the 2013 attack on the dam. Since then, a system upgrade and a new sluice gate have been installed.

Prosecutors said Firoozi was able to get access to information about the gate for the dam and the water levels in the Blind Brook, but he wasn’t able to control them. The reason was that the gate happened to be offline for maintenance at the time.

“The Bowman Avenue Dam, relatively speaking, is an inconsequential dam,” said Westchester County Executive Rob Astorino. “But what was proven was that they can hack into the system, and at some point in the future be able to control the operating system, raise the sluice gate, or worse.”

Astorino said the cyberattack on the dam shows the need for better communication between agencies. U.S. Attorney Preet Bhrarara called it a frightening new frontier of cybercrime.

“We now live in a world where a devastating attack on our financial system, our infrastructure, and our way of life can be launched from anywhere in the world,” Bharara said.

Bharara said everything will be done to catch those involved, and neighbors in Rye Brook hoped he meant it.

“If they were able to hack into the dam, what else could they do? Maybe hack into Indian Point (nuclear plant),” said David Vize of Rye. “So hopefully they find these creeps.”

“When it’s in your backyard, it’s scary — to bring it that close to home,” said Liz Johnson of Rye Brook, “but hopefully they’ll catch the people.”

U.S. Sen. Charles Schumer (D-N.Y.) also said earlier this month that the act against the dam should be met with stronger sanctions.

“What were they doing? They were sending a shot across our bow,” Schumer said. “They were saying that we can damage, seriously damage, our critical infrastructure and put the lives and property of people at risk.”

It’s the latest instance of the Obama administration publicly blaming foreign nations for damaging cyberbreaches.

The Justice Department in May 2014 indicted five Chinese military officials suspected of hacking into several major American companies — including U.S. Steel — and stealing trade secrets and confidential business information, though none of those defendants has been brought to the U.S. to face the charges.

In December 2014, the Obama administration publicly accused North Korea of being behind a punishing hack at Sony Pictures Entertainment.

Gov. Andrew Cuomo said cyber security is a top priority and his administration has implemented new measures to safeguard state infrastructure.

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