The governor of southern Russia's Rostov region, which sits on the border with Ukraine, told residents early on Saturday to remain calm and stay indoors, as the leader of the Wagner private military group led what Russia called a mutiny against the Moscow defense establishment.

"Law enforcement agencies are doing everything necessary to ensure the safety of residents of the area. I ask everyone to stay calm and not to leave home unless necessary," Vassily Golubev said in a message on his Telegram channel just before 4 a.m. local time.

Earlier, Wagner chief Yevgeny Prigozhin said his forces have entered Russia from Ukraine and are now in Rostov.