have spoken publicly, although Savchuk is one of the few willing to have her full name published. She quit after a little more than two months, after finding she couldn't stand being part of a propaganda machine.

The trolls are employed by Internet Research, which Russian news reports say is financed by a holding company headed by Putin's friend and personal chef. Those who have worked there say they have little doubt that the operation is run from the Kremlin.

St. Petersburg journalist Andrei Soshnikov, who was one of the first to report on the "troll factory," said about 400 people work in the building. A video he posted on YouTube this spring gave a rare glimpse inside the building; in one room trolls were shown sitting shoulder-to-shoulder at theircomputers. The operation moved into the building when it expanded in March 2014, the month Russia seized Crimea from Ukraine and provoked the first round of Western economic sanctions.

Soshnikov, a reporter at the weekly Moi Rayon, or My Region, said there has been a new push in recent months to hire more English-speaking trolls as part of an effort to sway public opinion in the United States.

"All of a sudden, (they) switch on Russia Today and realize that this is a holy land, Obama is a bloody dictator and true freedom of speech exists only in Russia."

In Serbia, trolls are recruited through several small right-wing parties that are both financially and politically supported by Russia, media analysts say.

When Russian opposition leader Boris Nemtsov was killed in Moscow in