Iranian computer hackers accessed the control system of a small dam outside of New York City two years ago, raising red flags throughout the U.S. government, according to a published report.

The Wall Street Journal reported that the Department of Homeland Security believes the hackers infiltrated the Bowman Avenue Dam in Rye Brook, N.Y. through a cellular modem. According to the Journal, investigators believe that hackers never actually took control of the dam itself, but merely probed the system.

Neither the White House nor DHS would comment specifically on the alleged incident when contacted by Fox News.

But DHS spokesman S.Y. Lee said in a statement: “The Department of Homeland Security continues to coordinate national efforts to strengthen the security and resilience of critical infrastructure, working with our federal and industry partners across the country to raise awareness about evolving threats and promote measures to reduce risks to systems we all rely on.”

The reported dam incident comes amid attacks by hackers linked to Iran’s government against the websites of U.S. banks and illustrates a prime concern of American officials: how to protect vulnerable American infrastructure from cyberattacks.

According to the Journal, the Department of Homeland Security was notified of 295 industrial-control-system hacking incidents over the 12 months ending Sept. 30. Over the previous 12 months, the number was 245.

Initially, intelligence analysts feared the hackers were targeting another dam: The Arthur R. Bowman Dam in Oregon, a 245-foot-tall earthen structure that irrigates local agriculture and prevents flooding near the town of Prineville, approximately 150 miles southeast of Portland. That belief prompted investigators to notify the White House that Iran had escalted its cyberwar with the United States.

The 22-foot-high Bowman Avenue Dam, built in 1941 for flood control, is described as "very, very small" by the manager of the nearby town of Rye, but its infiltration represents a fear among U.S. officials that government-backed hackers were more capable than first thought, and could inflict real-world damage.

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