Michael Flynn. Drew Angerer/Getty Images President-elect Donald Trump's national security adviser, Michael Flynn, met with the leader of a far-right Austrian political party that has close ties with Russian President Vladimir Putin, the Austrian leader said.

The Freedom Party leader, Heinz-Christian Strache, wrote on his Facebook page Monday that he met with Flynn "and a few other high-ranking US politicians" a few weeks ago at Trump Tower.

He noted in the post that his party had recently signed a cooperation deal with Putin's United Russia party, which "outlined plans for regular meetings and collaboration where suitable on economic, business, and political projects," The New York Times reported on Tuesday.

Flynn's relationship with the Kremlin has been under scrutiny since he was tapped by Trump to be the national security adviser. Photos have emerged of the former lieutenant general with Putin in Moscow celebrating the 10th anniversary of the state-sponsored news agency Russia Today, which has featured him as a commentator.

The fact that Flynn appears to have granted an audience to Strache in New York raises more questions about the influence that far-right populism and white nationalism may have on the incoming Trump administration.

The Freedom Party was founded in 1956, and its first leader was the far-right Austrian politician and Nazi Anton Reinthaller.

The Trump transition team did not respond to a request for comment.

Heinz-Christian Strache, the head of Austria's far-right Freedom Party. Heinz-Peter Bader/Reuters

Putin's recognition of Strache and his party via the reported cooperation deal — and Strache's apparent meeting with Flynn — also points to Russia's expanding influence over far-right movements in Europe and the United States.

That campaign has largely been part of an attempt to undermine support for the punishing sanctions the West imposed on Russia following Putin's annexation of Crimea in 2014, but is also more broadly aimed at establishing an alternative to the US-led status quo.

A right-wing conference in St. Petersburg, Russia, organized last year by Russia's nationalist Rodina, or Motherland, Party offered a safe space for fringe thinkers, including white supremacists and anti-Semitic figures, to gather and rail against the Western-dominated global order.

"If the radical nationalists are increasing their weight in Europe, they can serve as good allies for the Kremlin," Nikolai Petrov, a political scientist in Moscow, told The New York Times last year.

And many prominent "alt-right" figures in the US have courted their European counterparts in Hungary, Greece, and France in an attempt to build momentum for a "worldwide movement of globalism versus nationalism."

That's according to Matthew Heimbach, a self-described white nationalist, who said in a recent interview that the American alt-right "isn't just a European or a right-wing movement."

"Putin is supporting nationalists around the world and building an anti-globalist alliance," Heimbach said, "while promoting traditional values and self-determination."