Rostov region Governor Vasily Golubev is asking residents to stay calm and to not leave their homes.
"Dear fellow countrymen! The current situation requires a maximum concentration of all efforts to maintain order. Law enforcement agencies are doing everything necessary to ensure the safety of the region's residents. I ask everyone to stay calm and do not leave your homes unless it is necessary," Golubev said in a Telegram post Saturday.
The warnings come after Wagner chief Yevgeny Prigozhin said his fighters were entering the Russian Rostov region, which neighbors Ukraine. Prigozhin earlier vowed retaliation after accusing Russia's defense ministry of killing a "huge amount" of his mercenaries in a strike on a camp.