Marines reached a milestone this week when they landed side-by-side on a beach in Poland with their counterparts from the Russian military.

“It’s very historic,” said Marine Col. Lee Busby, commander of the combined landing force that hit the Gdynia, Poland, beach Wednesday in a training exercise.

About 170 troops from the Marines, Russian Naval Infantry, and Polish, Danish and Lithuanian militaries participated in the landing.

Last year Russia was added to the U.S. European Command’s area of responsibility. Since then, top U.S. Marines and leaders of the Russian Naval Infantry, akin to the Marines, have met in Russia and in Stuttgart, Germany, home of EUCOM. This is the first time the Marines and Russian Naval Infantry have participated in a larger-scale training exercise.

The landing was part of the 31st annual Baltic