More than 8,000 ground troops began drills set to last until early April in regions including southern Russia, Crimea, Armenia and the breakaway Georgian regions of South Ossetia and Abkhazia, defence ministry officials said.
The exercises are among the largest in recent times, the RIA Novosti news agency reported.
Russia's Black Sea fleet based in Crimea also began separate drills, using military planes to simulate an attack on its missile-carrying ships.
Around 200 Russian troops in central Russia underwent training to simulate urban warfare, using tanks and armed personnel carriers to "storm a city," defence officials said.
In February, Russia launched massive drills involving several thousand soldiers close to its borders with Baltic states already jittery over their former Soviet master's actions in Ukraine.
The United States then launched a three-month military exercise in Estonia, Latvia and Lithuania, deploying some 3,000 frontline troops to take part in drills in what officials said was meant to "demonstrate resolve to President (Vladimir) Putin and Russia that collectively we can come together."
He has since been accused by the West of backing and arming separatist rebels in eastern Ukraine in a conflict that has left some 6,000 dead. The Kremlin denies this.
NATO is countering Russia by boosting its defenses on Europe's eastern flank with a spearhead force of 5,000 troops and command centres in the Baltic states, Bulgaria, Poland and Romania.
