ADAZI, Latvia—The North Atlantic Treaty Organization said its deterrent force is fully in place in the Baltic area with the addition of a Canadian-led battle group in Latvia, enhancing deployments criticized by Russia.

A ceremony on Monday, featuring parading troops from Latvia, Canada, Poland, Italy, Spain, Slovenia and Albania, marked complete deployment of the fourth and final alliance battle group to the Baltic region. In all, NATO has positioned some 4,500 troops in Latvia, Lithuania, Estonia and Poland.

Allied and Russian forces have both been building up in the Baltic region. The deployments have raised the risk of miscalculation, some analysts said, but both sides have said they are necessary defensive initiatives.

The U.S. has deployed a tank brigade to Central and Eastern Europe and is conducting exercises in the Baltic Sea region. This month, the U.S. flew B-2 stealth bombers to Europe for what American military officials called a demonstration of reassurance for allies. The U.S. has also deployed other bombers and Army units for exercises in the Baltic Sea area.

Russia, too, is enlarging its forces. It is creating a larger permanent military presence in the region, including missiles and new army units, moves it says counter the NATO deployments. Russia and Belarus are also preparing for a large military exercise in September.