The US national power grid is subject to physical or online attacks around once every four days, a report by USA Today reveals.

The US national power grid is subject to physical or online attacks around once every four days, a report by USA Today reveals.

The examination, undertaken in collaboration with newspapers and TV stations around the country drew on “thousands of pages of government records, federal energy data and a survey of more than 50 electric utilities.”

It found that more than once a week, the security mechanisms designed to protect Americans from power outages are affected by attacks, and less severe ones happen more frequently still.

In fact, between 2011 and 2014, the US Department of Energy received 362 reports of physical or cyberattacks interrupting power services. Worse still, according to Time, the trend shows the attacks are getting more frequent, with just 31 reported in 2011, rising to 161 in 2013.

IT Pro Portal reports that there are “growing fears” that terrorists groups could be responsible for attempts to hack into the power grids. They also speculate that organized criminal gangs could use the threat of power outages to hold major cities to ransom.

Darren Hammell, chief strategy officer at energy management firm Princeton Power Systems told Fox News that the power grid remains “very vulnerable,” and that the country should be prepared for more.

Cheryl LaFleur, the Federal Energy Regulatory Commission Chairman explained to USA Today how seriously the industry is taking the threats facing the industry: “It’s one of those things: One is too many, so that’s why we have to pay attention.”

“The threats continue to evolve, and we have to continue to evolve as well.”