Troops from over 20 countries are taking part in the massive exercise in Poland, amid severe tensions between NATO and Moscow. The maneuvers test the alliance's ability to "defend its eastern flank," Warsaw said.
Defense Minister Antoni Macierewicz and US Ambassador Paul W. Jones opened the NATO Anaconda-16 exercise in Warsaw on Monday with the operations starting on Tuesday.
The maneuvers include a nighttime helicopter assault, US paratroopers building a temporary bridge, and a response to surprise attack from the east. Non-NATO countries such as Sweden and Finland are also involved in the drill.
According to Defense Minister Macierewicz, the drills are aimed at "checking the alliance's ability to defend its eastern flank."
Some 31,000 troops are set to take part in the 10-day drill, including 14,000 US soldiers and 12,000 Polish troopers, with 105 airplanes and 12 Navy ships.
Missile shield brings new divisions
The exercise opens a month ahead of a large NATO summit in Poland, where the member nations would discuss perceived threats from Russia, boosted by conflict in neighboring Ukraine. The alliance is expected to move more troops to eastern Europe.
Russia has repeatedly decried the NATO build-up near its borders. The Kremlin also slammed the US missile shield - for which construction began in Romania and Poland last month - as an attempt to curb Moscow's nuclear power.
In response to NATO expansion, Russian officials often cite a 1997 agreement when NATO pledged not to create permanent bases in former eastern bloc states. US officials, however, claim that the troops would be rotated rather then stationed permanently.
Protecting 'NATO bureaucracy'
On Monday, Russia's Defense Ministry spokesman Igor Konashenkov said that some US and NATO representatives were feeding anti-Russian "hysteria."
"If you take a listen, you get this impression that NATO is a cornered sheep with predators all around, embodied by Russia and other countries that are not under the US control," he told reporters in Moscow.
Konashenkov also accused "Cold War pensioners" of boosting fears of the Russian threat, and ultimately "protecting NATO bureaucracy from the attack of the states' taxpayers."
"This year's culmination of this spectacle would be in Warsaw on July 8," he said, referring to the upcoming NATO summit in Poland.
Earlier, Moscow pledged to set up three new divisions in the west and the south of the country. Russia's military also considered placing its nuclear-capable missiles in its Kaliningrad exclave, which is wedged between Poland and Lithuania.