President Biden announced Wednesday during the NATO summit in Madrid steps that the US will take to increase its military presence in Europe, including the establishment of a permanent base in Poland.

The base in Poland will mark the first time the US will establish an official permanent military facility in the area known as NATO's "eastern flank." The US military presence elsewhere in Eastern Europe and in the Baltic states is technically on a rotational basis, although Washington has no plans to scale back its presence in the region.

Under the 1997 NATO-Russia Founding Act, NATO agreed not to establish a permanent military presence east of Germany. US officials insist the base in Poland does not violate the act since it is only a permanent facility, and the troops will be deployed rotationally, but it's unlikely Moscow will see it that way.