THE United States placed five Russian companies and three individuals on its sanctions blacklist on Monday for allegedly supporting the FSB intelligence agency’s hacking operations, including a firm involved in subsea operations.

The US Treasury named Digital Security and two subsidiaries as helping develop offensive cyber capabilities for Russian intelligence services, including the already-sanctioned FSB.

The Kvant Scientific Research Institute was also included on the blacklist, as a state enterprise supervised by the FSB.

In addition, Divetechnoservices and three officials of the firm were sanctioned for supplying and supporting the government’s underwater capabilities in monitoring and hacking subsea communications cables around the world.

US officials have become alarmed over the past year at the extent of US-targeted offensive cyber operations that Washington alleges have official backing from Moscow.

Those include the global NotPetya cyber attack, which paralysed thousands of computers around the world last year; intrusions into the control systems of the US energy grid; and the insertion of trojans into home and company networking devices around the world, which allow both the diversion of data and attacks that could shut down networks.

The sanctions freeze property and assets under US jurisdiction and seek to lock those named out of global financial networks.