Seven hackers tied to the Iranian government were charged Thursday in a series of punishing cyberattacks on a small dam in Westchester County and on dozens of banks — intrusions that reached into American infrastructure and disrupted the financial system, federal law enforcement officials said.

The hackers were charged in indictments unsealed and announced at a Justice Department news conference in Washington.

All seven worked for Iranian computer companies that did work on behalf of the Iranian government, the U.S. said.

The attacks, launched between 2011 and 2013, disabled bank websites and caused tens of millions of dollars in losses, according to the indictment.

One of the seven, Hamid Firoozi, 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.

The dam's digitally controlled sluice gate had been installed a few months before the hack and hadn't been hooked up to the computer system.

However, Firoozi was able to gain information about the dam's operations — which include water level, temperature and the gate itself.

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 message of this case is that we will work together to shrink the world and impose costs on these people, so that no matter where they are, we will reach them," FBI Director James Comey said.

It's the latest instance of the Obama administration publicly blaming foreign nations for damaging cyber intrusions.

The Justice Department in May 2014 indicted five Chinese military officials suspected of hacking into several major American companies and stealing trade secrets.

And that December, the federal government linked a damaging attack on Sony Pictures Entertainment to North Koreans.