The notice went out on Facebook last year, calling citizens of Twin Falls, Idaho, to an urgent meeting about the “huge upsurge of violence toward American citizens” by Muslim refugees who had settled there.

The inflammatory post, however, originated not in Idaho but in Russia. The meeting’s sponsor, an anti-immigrant page called “Secured Borders,” was one of hundreds of fake Facebook accounts created by a Russian company with Kremlin ties to spread vitriolic messages on divisive issues.

Facebook acknowledged last week that it had closed the accounts after linking them to advertisements costing $100,000 that were purchased in Russia’s influence campaign during and after the 2016 election. But the company declined to release or describe in detail the pages and profiles it had linked to Russia.

A report by the Russian media outlet RBC last March, however, identified the Secured Borders page as the work of the Internet Research Agency, a St. Petersburg firm that employs hundreds of so-called trolls to post material in support of Russian government policies. A Facebook official confirmed that Secured Borders was removed in the purge of Russian fakes.