Around 4,700 troops and 800 military vehicles from 10 NATO including Britain and the United States are participating in the Sabre Strike exercises near the Latvian capital Riga.
Russia has voiced its objections to the manoeuvres, which move to neighbouring Lithuania on Tuesday.
The exercises come as Moscow´s March annexation of Crimea and sabre rattling in the Russian exclave of Kaliningrad have sparked fear in the neighbouring Baltics.
Estonia, Latvia and Lithuania were unwilling Soviet republics until the 1990-91 collapse of the USSR. They joined NATO and the EU in 2004.
“The exercise is very important given the current security situation,” Latvian Defense Minister Raimonds Vejonis told reporters, citing the Ukraine crisis.
Russia was quick to label the games an “act of aggression,” according to the Interfax news agency.
“We can´t take this military buildup by the alliance next to Russia´s borders as anything but a demonstration of hostile intent,” Russian Deputy Foreign Minister Vladimir Titov told Interfax.
“The deployment of extra NATO troops in Central and Eastern Europe, even on a rotational basis is a violation of Russia´s agreements with the alliance.”
