Lt. Col. Eero Rebo, deputy chief of the general staff, told ETV that Estonia was currently in "close consultations" with NATO and Baltic partners and following the course of the exercise, Zapad 2013.
"But there is no reason for concern or major panic either from Estonia or NATO as a whole," Rebo said.
According to reports, Russia was test-firing several of the intermediate range missiles it has stationed close to the Estonian border.
The Russian missile forces and the Western district's artillery are conducting test firings of Iskander, Tochka, Smech and Uragan missiles, according to Russian news agencies.
Rebo said the scope of the exercises has grown in recent days. "There was talk of 12,900 personnel, but we have heard figures on the Russian news that far, far exceed that."
"Whether it's 50,000 or even more, I can't say right now," he added.
Rebo said a number of exercises appear to be running concurrently with Zapad.
Rebo added that the official pretext of Zapad 2013 being a counter-terrorism exercise could "not be taken seriously." He said the type of weapons and services being used - tanks, missiles and amphibious landings - would not be much use in asymmetric warfare.