Domestic violent extremists have in the last year increasingly shared tactics with each other on using guns to attack electric power stations in a move that likely escalates the threat to US critical infrastructure, according to a Department of Homeland Security bulletin obtained by CNN. Following multiple high-profile attacks on US power substations last year, extremists have stepped up sharing of “online messaging and operational guidance promoting attacks against this sector,” says the DHS bulletin, which was distributed to US critical infrastructure operators on Monday. The information and tactics shared by extremists online include “detailed diagrams, simplified tips for enhancing operational security, and procedures for disabling key components of substations and transformers,” DHS warned. The last year saw a flurry of physical attacks and vandalism on US electric infrastructure. Tens of thousands of people lost power in Moore County, North Carolina, in December after Duke Energy substations were damaged by gunfire. On Christmas, thousands of people lost power in a Washington county after someone vandalized multiple substations there. A DHS spokesperson told CNN in a statement: “The Department of Homeland Security regularly shares information regarding the heightened threat environment with federal, state, local, tribal, and territorial officials to ensure the safety and security of all communities across the country.” Some of the threats to electric infrastructure have come from people espousing racially or ethnically motivated extremist ideology “to create civil disorder and inspire further violence,” the FBI previously said in a November bulletin sent to private industry.

viancnn: Violent extremists are increasingly sharing tactics for attacking power stations, DHS warns