An extensive, Russian-backed hacking operation targeted the email accounts of thousands of perceived Kremlin adversaries in 2015 and 2016, an Associated Press investigation has learned .

The effort, broadly referred to as Iron Twilight by security researchers, sought to compromise 4,700 Gmail accounts worldwide, belonging to everyone from high-profile U.S. politicians including Hillary Clinton, John Podesta and Colin Powell, who were all hacked to academics, journalists, political activists and military personnel.

Who they targeted

According to information provided by Secureworks , the cybersecurity firm whose data underpins much of the AP report, theres a clear link between the targeted email accounts and Russias targets in the real world.

A spokesperson for the prime minister of Ukraine, for instance where Russian forces are currently engaged in a military conflict was targeted nine times, Secureworks said.

Other targeted individuals identified by the AP include former Secretary of State John Kerry, former NATO Supreme Commander U.S. Air Force Gen. Philip Breedlove, and Serhiy Leshchenko, a Ukranian politician who helped reveal alleged financial crimes of Paul Manafort, who was indicted Monday.

Experts on Ukrainian and Russian subject matters, as well as aerospace researchers and engineers were also among those targeted.

Military spouses and family members also constituted a surprisingly large portion of those targeted, which Secureworks speculates may be an attempt to learn about broader military issues in the U.S., or to gain information about the targets spouse.

Of the military and government personnel who were targeted, the vast majority are either in the U.S. or a member of NATO: