U.S. defense officials have made an offer to permanently station U.S. troops in Poland, though it’s still a few years away from being a possible duty assignment.

Under Secretary of Defense for Policy John Rood is meeting with Polish counterparts this week in Warsaw to negotiate the deal, but an offer to Poland has already been made.

The Poles themselves have offered to contribute at least $2 billion, and perhaps more, to the potential base, which would serve to balance against Russian aggression in Eastern Europe, defense officials say.

“We have come forward with what we think is a very serious robust offer, and we’re just working out some of the technicalities this very week,” Kathryn Wheelbarger, the acting assistant secretary of defense for international security affairs, told the House Armed Services Committee Wednesday. “We hope to have a solid foundation to work from ... coming out of this meeting.”

Russian aggression on the rise in the Balkans, Army four-star says U.S. military units and allies at their highest readiness rate in years, the U.S. commander in Europe says.

The U.S. currently has troops that rotate through Poland, such as Army brigade combat teams and Air Force Reaper pilots, but the potential base would lock in a permanent foothold for the U.S.

Polish President Andrzej Duda jokingly referred to the base as “Fort Trump” during a press conference with President Donald Trump in the fall.

Gen. Curtis Scaparrotti, head of U.S. European Command and the NATO Supreme Allied Commander-Europe, said at the House hearing that he wants to maintain a mix of rotational and permanent forces in Poland.

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Rotating troops through Poland breeds a better understanding of the European theater for U.S. forces not permanently assigned there, according to Scaparrotti.

But when it comes to the enablers, headquarters troops and other personnel, “a more permanent base is helpful because of the relationships you build and the mission they have,” Scaparrotti said. “So you’ll see a little bit of a combination there from my point of view.”

Air Force MQ-9 Reaper drones based in Poland are now fully operational Poland was chosen as a location for the mission due to its “strategic location in Eastern Europe."

There’s no guarantee that the U.S. and Poland will come to an agreement in their discussions this week, but Polish officials have been seriously interested in basing Americans in the country in order to provide a bulwark against Russia, which they view as a serious threat.

“If we come to ... agreed terms on the foundation of our offer and their acceptance of that, we would then go to the State Department and seek the authority for the State Department to then be the lead negotiator for, again, the actual technical agreement that would be signed," Wheelbarger said.

It would take six months to a year for that agreement to be finalized, she added.

“It’s a couple of years, two to three years off, before we would be dealing with an actual base and the money for that base,” Scaparrotti said.

An Air Force joint terminal attack controller lases targets during close air support training mission July 29, 2015, conducted with Polish troops. (Master Sgt. Scott Thompson/Air Force)

Establishing a new U.S. military base in Poland won’t necessitate cuts from U.S. troop numbers in Germany, Kay Bailey Hutchison, the U.S. ambassador to NATO, said in February.

“It wouldn’t be at the expense of Germany,” Hutchison told reporters during a telephone conference. “We have a very large number of forces and bases in Germany that we don’t expect to change."

The Polish defense ministry proposal that was leaked to the press in May lists the country’s regions of Bydgoszcz and Toruń as possible locations for the hypothetical U.S. base. Those regions were selected based on their proximity to ranges, infrastructure, accommodations, and morale and welfare options for U.S. troops, according to the document.