The U.S. Army will send tanks this week to countries on Russia’s frontiers in the largest such deployment since the Cold War, a step aimed at reassuring America’s European allies that Washington remains committed to their defense.

After joint U.S.-Polish exercises in northern Poland on Monday, some of the M1A2 Abrams main battle tanks used in the drills will be transported to the Baltic states of Latvia, Estonia and Lithuania, where they will remain until a new North Atlantic Treaty Organization deterrent force is operational in the spring.

In recent days, allies have pointed to the deployment of American troops and military hardware in Eastern Europe as a sign the U.S. remains committed to NATO and that the alliance will carry out its policy of building a force to thwart any Russian military action in the region.

“The physical presence of NATO is here with us today,” Polish President Andrzej Duda said on Monday at a ceremony in Zagan, Poland, with the U.S. Army’s 3rd Armored Combat Brigade Team of the 4th Infantry Division.

The exercises were planned before Donald Trump was elected U.S. president in November. Since then, allied officials have privately expressed worries about the administration’s policy toward NATO and whether the White House will curtail the deployment.