U.S. authorities have seized dozens of Internet domains that Russian intelligence-backed hackers used as part of a sophisticated campaign to gain access to U.S. government computers.

U.S. authorities and Microsoft say hackers linked to Russian intelligence targeted dozens of former military and intelligence officials, journalists and civil society groups with a sophisticated campa

The domains were allegedly staging grounds for Russia’s FSB intelligence agency in its ongoing efforts to spy on targets of interest, ranging from the U.S. Department of Energy to Russian nonprofits and media outlets critical of the Kremlin.