The U.S. State Department has called in Russia's chargé d'affaires in Washington over what it says are Moscow’s efforts to use social media to “promote violence” and divide U.S. society. Russia criticized the summons, calling it "megaphone diplomacy."

In a Twitter posting on August 5, department spokeswoman Heather Nauert wrote: "Assistant Secretary [Wess] Mitchell convoked #Russia Chargé [Dmitry] Zhirnov to answer for the Kremlin's attempts to use social media accounts to promote violent and divisive causes in the U.S. -- we will not tolerate this aggressive interference."

The tweet linked to a statement issued on August 1 regarding Facebook's July 31 announcement that it had discovered "sophisticated" efforts, possibly linked to Russia, to manipulate U.S. politics ahead of November's congressional elections.

The social-media giant said it could not connect the efforts directly to Russia or to the midterm elections, which are less than 100 days away, but legislators briefed by Facebook said the methodology used by the perpetrators pointed to Russian involvement.

"We applaud Facebook's decision to expunge accounts, orchestrated from abroad, that foment division and violence inside the United States," Nauert's August 1 statement said.

"We demand that Russia and all other malign actors immediately cease this reckless behavior," it added.

"The United States will not tolerate foreign, including Russian, attempts to subvert our democratic processes and institutions."

The Russian Embassy in Washington fired back in a statement later on August 5, reiterating Moscow's denials of interference in U.S. affairs. The United States has rejected those denials.

"We can only express regret that the State Department is once again stooping to 'megaphone diplomacy,'" the embassy said.

It accused the State Department of "playing up to those forces in the American establishment who promote the theme of 'Russian meddling' in U.S. political processes for their own gain."

The U.S. intelligence community has concluded that Russia interfered in the 2016 U.S. presidential election and has used social media to divide U.S. society over sensitive issues.

On August 2, leaders of the U.S. intelligence and security community told a briefing at the White House that Russia was continuing to use "pervasive methods" to exploit and intensify differences in U.S. society and that they remain concerned about U.S. election security.

"We continue to see a pervasive messaging campaign by Russia to try to weaken and divide the United States," said Dan Coats, the director of national intelligence.

Russia denies that it has interfered in the U.S. election or has attempted to divide U.S society through social media.