US Army tanks arrive in Poland as Russia begins military drills The delivery occurs as Russia conducts a large military exercise.

 -- As Russia began large military exercises on its western border, the U.S. Army was unloading tanks in Poland, the first time these military vehicles have arrived directly by sea.

The tanks, which arrived on Wednesday, are part of a routine troop swap. Soldiers and equipment from the 2nd Armored Brigade Combat Team, 1st Infantry Division from Fort Riley, Kansas, are replacing the 3rd Armored Brigade Combat Team, 4th Infantry Division that has been in Europe for nine months.

The replacement is part of what the military calls a continuing "heel-to-toe" rotation to maintain a U.S. armored brigade in Europe.

As for the tanks, they typically are shipped to Germany and then taken by rail or truck to their next location.

Maj. Gen. Steven Shapiro of the 21st Theater Sustainment Command said using Poland's port of Gdansk "helps test the Army's capacity of the port, and to make sure that the Army knows how to operate inside Poland."

The delivery includes 87 M1 Abrams tanks, 103 Bradley Fighting Vehicles, 18 Paladin self-propelled Howitzers, and other trucks and equipment, according to U.S. European Command (EUCOM).

"The continuous presence of an armored brigade bolsters the collective defense capability of NATO," EUCOM said. "EUCOM forces live, train, and fight alongside and partners from strategic positions that enable more timely and coordinated response if needed to defend Europe."

The U.S. military rotation occurred as Russia began week-long military drills, called Zapad 2017, which are joint exercises with its ally Belarus.

According to the Russians, the drills involve fewer than 12,000 troops, just below the threshold that would require them to invite international observers. But, according to the U.S. and NATO, the drills could involve as many as 100,000 troops, making it one of the largest Russian exercises since the Cold War.