The exercise in Ukraine comes as Russia is gearing up for its major military exercise, Zapad 2017, which is expected to involve tens of thousands of troops operating along NATO's borders in Western Russia, the Russian European enclave of Kaliningrad and Belarus. Estonia's defense minister, Margus Tsahkna, has pointed to a document showing that Russia's military has requisitioned over 4,000 rail cars for the war games, suggesting that the number of troops who will be traveling will be far more than the 12,700 Moscow says are taking part.
The US military commander in Europe, Lt General Ben Hodges, echoed such concerns in an interview this summer, admitting that: "people are anxious this is a Trojan horse".
Ukraine has already increased its security alert level out of fear that the exercise will be used as a Trojan horse for another Russian invasion.
"There are many doubts and fears that, because of the Russian federation's previous actions, not all forces and equipment will be removed [from Belarus] after the exercise", he told reporters in Warsaw on Wednesday.
Despite NATO countries taking part in the massive Swedish drills - some of which are again taking place near Kaliningrad - the alliance has no problem slamming Russian Federation for conducting a much smaller exercise with Belarus.
In one of the biggest shows of military might since the end of the Cold War, Russia and Belarus are conducting joint maneuvers on NATO's doorstep, where the exercises are prompting jitters in some former Soviet satellites.
Russia, which has the most nuclear warheads in the world, is now working to build up its conventional weapons capabilities to match the U.S., Kofman said.
"It is all smoke and mirrors", the official said, adding the Soviet-era Zapad exercises that were revived in 1999 had included simulated nuclear strikes on Europe.
As a precaution, the U.S. military has moved 600 paratroopers to the Baltics during Zapad and has taken over guardianship of the airspace of Lithuania, Latvia and Estonia, which lack capable air forces and air defence systems.
Lithuanian President Dalia Grybauskaite, who often criticizes Russian leaders, said the war games are a sign the Kremlin is preparing for conflict with North Atlantic Treaty Organisation.
NATO, however, believes - without evidence - that more troops will be involved.
And despite assurances from Minsk and Moscow, leaders in Poland, the Baltic states, Slovakia, Romania, the Ukraine and Bulgaria are concerned Russian Federation might not pull back all of its soldiers after the drills.
"Russia is the country that affects security in Europe right now with its actions - the annexation of the Crimea and continued battles in eastern Ukraine - so it is clear that we are watching very closely what Russian Federation is doing", Byden said.
It was all those railway wagons that got the speculation rolling over Russian intentions with its military exercises this week along its western borders.