U.S. soldiers with the 173rd Infantry Brigade Combat Team parachute Monday, June 15, from a C-17 aircraft along with an M119 105mm towed Howitzer at the Drawsko Pomorskie Training Area in Poland during exercise Saber Strike 15. (Photo by Spec. Marcus Floyd/ U.S. Army)

The parachutes dropped into Poland on Monday in bunches, carrying U.S. paratroopers and pieces of a powerful M119 Howitzer to be assembled on the ground. It’s part of a training exercise designed to keep U.S. and European troops sharp. It’s also something more: A piece of a broad military exercise spanning multiple countries on Russia’s doorstep.

Saber Strike 15, scheduled from June 8 through 19, is the latest iteration of an exercise that dates back to at least 2010. But it continues to grow, as countries on Europe’s eastern flank register concern about Russian aggression in Ukraine. This year’s version includes at least 6,000 troops from 13 countries, military officials said. That’s up from 4,500 troops from 10 countries last year.

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The latest version of the exercise includes troops from Canada, Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Norway, Poland, Portugal, Slovenia, the United Kingdom and the United States. Germany, Portugal and Slovenia are the latest countries to join. Denmark and Canada participated for the first time in 2014.

In addition to Poland, the exercise includes operations in Latvia and Lithuania, countries that were formerly part of the Soviet Union and have joined NATO. Here are some photographs of the action, which includes a simulated bombing run by an A-10 attack plane, tank operations and a military assault:


U.S. soldiers with the 173rd Infantry Brigade Combat Team parachute Monday, June 15, from a C-17 aircraft along with an M119 105mm towed Howitzer at the Drawsko Pomorskie Training Area in Poland during exercise Saber Strike 15. (Photo by Spec. Marcus Floyd/ U.S. Army)

U.S. soldiers with the 173rd Infantry Brigade Combat Team airdrop from a C-17 on Monday, June 15, at the Drawsko Pomorskie Training Area in Poland during Saber Strike 15. (Photo by Spec. Marcus Floyd/ U.S. Army)

A U.S. Marine with its Black Sea Rotational Force based in Romania takes part in Saber Strike 15 at the Pabrade Training Area, Lithuania. (Defense Department photo)

An A-10C Thunderbolt II attack jet flies over to simulate a bombing run in support of ground troops during exercise Saber Strike 15 near Rukla, Lithuania, on June 12, 2015. (Photo by Sgt. Jarred Woods/ U.S. Army)

German soldiers hide their Wiesel A2 TOW track vehicle in thick underbrush June 10, 2015, at the Great Lithuanian Hetman Jonusas Radvila Training Regiment, in Rukla, Lithuania. (Photo by Sgt. James Avery/ U.S. Army)