The exercises, codenamed "Zapad" or "West", started on Thursday and will be held until September 20 on military ranges in Belarus, western Russia, Russia's exclave of Kaliningrad and in the Baltic Sea.
One senior European security official said Zapad would merge manoeuvres across Russia's four western military districts in a "complex, multi-dimensional aggressive, anti-NATO exercise".
The exercises involve up to 12,700 troops, 70 warplanes and helicopters, 680 units of military equipment, including about 250 tanks, 200 guns, numerous rocket launchers and mortars and 10 warships, the ministry said.
Ukraine's President Petro Poroshenko has warned - while speaking in the country's parliament - that the drills show that Russian Federation is "preparing for an offensive war of continental proportions" and planning "a new assault group.to strike Ukrainian territory".
She also noticed that the exercises are already taking place, although they officially will begin only today.
Latvian President Raimonds Vejonis said "we should not succumb to intimidation", describing Zapad as an attempt to make the Baltic states feel insecure.
However, NATO officials say the number of troops is much larger than Moscow has publicised, closer to 100,000.
Russia's neighbors have gotten the message, and some fear the Russians may have another, more nefarious goal in mind with this year's Zapad (Russian for "West").
ZAPAD 2017 has also sparked concerns among NATO's easternmost members that Russian forces may stay in the area following the conclusion of the exercise. Compared to the U.S, Russian Federation is still a military underdog, and the fact that Belarus is its only partner in these exercises goes to show how Moscow's network of alliances has withered since Soviet times.
NATO Secretary-General Jens Stoltenberg said in Estonia last week that the military alliance would send three observers.
The main goals of the drills are to "update the operational compatibility of headquarters at different levels, promote the interoperability of prospective forces and weapons control systems, test new charter documents, and allow commanders of all ranks to practice planning events of a military nature and commanding forces on the basis of modern armed-conflict experience", the statement said. "The danger of incidents or accidents has increased because there are more troops, more military forces along our borders, there are more exercises, and that's exactly why we are so focused on transparency, predictability", NATO's chief added.
"The last thing we want is a military escalation with Russian Federation", said one senior North Atlantic Treaty Organisation official involved in military planning, referring to Zapad.
But military analysts on both sides say the figures were misunderstood, and that the number of troops Russian Federation claims to have sent west do stack up. "History teaches us that we need to see and watch and prepare for the activities of Russian Federation", she added.