As US President Donald Trump threatens wholesale demolition of Iran's infrastructure in the midst of an escalating war, Iran now appears to have already reciprocated with its own form of infrastructure sabotage: A hacking campaign hitting industrial control systems across the United States, including energy and water utilities, that US agencies say has had disruptive and costly effects.

In a joint advisory published Tuesday, a group of US agencies including the FBI, the National Security Agency, the Department of Energy, and the Cybersecurity and Infrastructure Security Agency warned that a group of hackers affiliated with the Iranian government has targeted industrial control devices used in a series of critical infrastructure targets including in the energy sector, water and wastewater utilities, and unspecified “government facilities.” According to the agencies, the hackers have targeted programmable logic controllers (PLCs)—a type of device designed to allow digital control of physical machinery—in those facilities, including those sold by industrial tech firm Rockwell Automation, with the apparent intention of sabotaging their systems.

By compromising those PLCs, the advisory warns, the hackers sought to change information on the displays of industrial control systems, which can in some scenarios cause system downtime, damage, or even dangerous conditions. “In a few cases, this activity has resulted in operational disruption and financial loss,” it reads.

When WIRED reached out to Rockwell Automation, a company spokesperson responded in a statement that it “takes seriously the security of its products and solutions and has been closely coordinating with government agencies in connection with” Tuesday's advisory, and pointed to