Although the move is only really taking place now in the waning days of the Obama administration, the NATO movement of heavy armament and 1,000 U.S. troops to poland over the past week was actually scheduled more than 6 months ago.
Atlantic Resolve
The maneuvers, code named Atlantic Resolve, will eventually see 4,000 U.S. combat troops from the NATO command moving to backup Polish troops in a clear signal to Russia that Putin needs to keep hands off Poland.
There is an agreement with Russia not to place permanent troops near the Russian border so, although Atlantic Resolve is definitely a long-term deployment, possibly permanent, the actual troops will be rotated about once a year so they remain technically a temporary force and within the agreement.
Russia Times report
The best source of information appears to be the RT (formerly Russia Times) web site which puts the final deployment manifest at “87 Abrams M1A1” heavy battle tanks, “20 Paladin” mobile artillery, and “136 Bradley fighting vehicles” although RT credits some of the numbers to a Reuters report.
The four thousand troops will rotate through Poland, the Baltic, Bulgaria, and Romania.
Army Airborne
According to the Department of the Army (U.S.) also scheduled to round out the combat capability will be 1,750 personnel from Fort Drum New York's 10th Combat Aviation Brigade, 10th Mountain Division, which will be deployed in Eastern Europe with 50 Black Hawk helicopters and another 10 CH-47 Chinook helicopters.
An additional two dozen Apache helicopters along with crews and maintenance staff will also deploy to the region.
Moscow Trumped
Although Russia is complaining that this is an aggressive action, Putin isn't taking any obvious steps to oppose it other than in press statements, perhaps relying on President-elect Trump rolling back the move.
But that may change now that Trump’s nominee for Secretary of Defense, retired general James “Mad Dog” Mattis as well as the President-Elect’s nominee for Secretary of State Rex Tiller son both came out strongly in regard to the need to stand up to a newly aggressive Russia in their opening confirmation hearings.
Although not originally members of NATO because they were under the control of the U.S.S.R. as part of the Warsaw Pact, in 1997 Poland, Hungary, the Czech Republic were invited to join NATO, a military organization specifically built to counter Soviet Era Russia’s threats.