According to an indictment unsealed on Thursday morning, a series of cyber-attacks on U.S. financial institutions may have been committed between late 2011 and mid-2013 by alleged hackers linked to the Iranian government, with three of the Philadelphia region’s seven largest deposit takers among the victims, writes Jeff Blumenthal for the Philadelphia Business Journal.

In an extensive campaign of over 176 DDoS attacks against 46 victims, primarily U.S financial services companies, a number of institutions were targeted including Bank of America, PNC Bank and BB&T Corp. along with AT&T, the New York Stock Exchange and NASDAQ.

Federal prosecutors said that the attacks prevented customers from being able to access their bank accounts online and disabled the bank websites, collectively costing the victims tens of millions of dollars in remediation costs.

Welcoming the DOJ’s announcement, a PNC spokeswoman noted that no customer accounts or information were compromised, although they had experienced intermittent delays in accessing online banking during that time period.

BB&T only stated that during the alleged cyber-attack, its client accounts and information were not compromised. The North Carolina-based bank entered the regional market after the acquisition of Susquehanna Bancshares last year and plans to acquire National Penn Bancshares later this year.

Declining to comment, a Bank of America spokesman referred the inquiry to the Financial Services Information Sharing and Analysis Center and the American Bankers Association.

The U.S. Department of Justice in Manhattan has charged seven Iranians for the crimes, Hamid Firoozi, 34, Ahmad Fathi, 37, SinaKeissar, 25, Amin Shokohi, 25, Sadegh Ahmadzadegan, 23, Nader Saedi, 26 and Omid Ghaffarinia, 25.

In addition, prosecutors are charging Firoozi with obtaining unauthorized access to the Supervisory Control and Data Acquisition systems of the Bowman Dam in Rye, N.Y. between August and September, 2013.

To read more about alleged Iranian cyber-attacks on financial institutions see here