President-elect Donald Trump's pick for National Security Advisor, Lt. Gen. Michael Flynn met with the leader of an extreme Austrian political party founded by former Nazis, the New York Times reported Monday.

Gen. Flynn met with Heinz-Christian Strache, the leader of the Freedom Party, several weeks ago at the Trump Tower in New York City.

The Freedom Party was founded by former Nazis in the 1950s. It's candidate, Norbert Hofer, came close to winning the presidency in early December, and was narrowly defeated by independent candidate Alexander Van der Bellen. The Freedom Party currently leads all Austrian political parties in national polling.

It is unknown what Gen. Flynn and Strache spoke about during their meeting.

Strache disclosed that the meeting took place in a Facebook post Monday. He also revealed that the Freedom Party had signed a cooperation agreement with Russia’s ruling party in the same post.

Strache used the news of the meeting and the cooperation agreement to show Austrians that the Freedom Party has international standing and is a legitimate contender for political power, boasting that “the Freedom Party continues to gain international influence.”

Daniel Serwer, a professor at Johns Hopkins University specializing in foreign policy, told the Huffington Post that the Freedom Party "is not just any opposition party: It is one with Nazi sympathies.”