Speaking at a press conference after an official visit with President Trump on Tuesday, Polish President Andrzej Duda dropped a surprising proposal for the U.S. military to establish a permanent presence in Poland by opening a large base, and went so far as to suggest it would be called "Fort Trump".

The remarks, which were clearly designed to play on the president's ego, came amidst joint statements wherein both leaders agreed that Moscow has "acted aggressively" in the region. Trump said that he shared concerns about Russian encroachment into former Soviet satellite countries.

Trump grinned the moment President Duda uttered "Fort Trump". Image source: Getty

Poland, a NATO member state, has long sought to invite closer military relations with the United States, something which Moscow has seen as a serious provocation.

President Duda offered to put more than $2 billion into a proposed permanent American base, to which Trump responded with appreciation.

.@realDonaldTrump's facial expression when hearing Poland might name a military base "Fort Trump" is priceless. pic.twitter.com/wohVn1bLfi — The Daily Caller (@DailyCaller) September 18, 2018

"I invite you to post more American military troops in Poland," Duda said, describing US presence in Poland as a "guarantor of security."

"We're looking at it very seriously, I know Poland likes the idea very much, and it's something that we are considering, yes," Trump told reporters, according to CNN.

President Trump appeared to nod and grin at the moment Duda dropped the "Fort Trump" idea.

Meanwhile Moscow has previously expressed alarm as recently as May over Poland's pushing for an American base so close to Russia's border.

Poland jointed NATO in 1999 along with Hungary and the Czech Republic, in what Russia has legitimately feared is a domino effect that eventually included Baltic states joining up.

U.S. Defense Secretary Jim Mattis has long said the US is studying the option of a US base in Poland. Related to the Trump-Duda press conference, Mattis told reporters, "It’s not just about a base. It’s about training ranges, it’s about maintenance facilities at the base, all these kinds of things. There’s a host of details we’ve got to study alongside the Poles.”

Of the Polish president's proposal and expressed willingness to foot a significant chunk of the bill, Trump said, "He would pay the United States, meaning Poland would be paying billions of dollars for a base." He added, "We're looking at that more and more from the standpoint of defending really wealthy countries."