That's what the US Army said on Twitter.
The troops from 3rd Armored Brigade Combat Team, 4th Infantry Division are arriving via planes from Fort Carson in Colorado while heavy equipment was being unloaded in Germany's Bremerhaven port.
Among other equipment, a total of 87 Abrams tanks, 144 Bradley vehicles and 18 Paladin artillery are arriving to Europe for nine months as part of a NATO deterrence mission.
The deployment should conclude be February, with the HQ located in Poland and other parts divided between the Baltics. A single battalion will be deployed in Bulgaria and Romania each, as well as in Germany.
The air force component of more than 60 combat helicopters is to arrive in February.
The forces are arriving as part of the US' European Reassurance Initiative, which costs about $3.4 billion.
Poland and the Baltics are concerned about heightened Russian military in the region following Russia's 2014 invasion of Crimea. The countries have asked NATO and the US to send troops for deterrence against what is seen as a Russian threat.