The Department of State has temporarily suspended all nonimmigrant visa operations at U.S. consular offices in Russia, due to the personnel cap imposed by the Russian government. The suspension starts August 23, 2017, and reduced operations will resume on September 1, 2017. At that time, nonimmigrant visa interviews will be conducted only at the U.S. Embassy in Moscow. This will likely cause backlogs in appointment and processing times, with the Embassy giving priority to diplomatic applications and those involving medical or family emergencies.
The Department has posted a Fact Sheet with further details https://ru.usembassy.gov/fact-sheet/.