White nationalist leader Richard Spencer was reportedly stopped by authorities in Europe this week while attempting to travel to address young white nationalists.

Spencer seemingly confirmed the incident Thursday on Twitter, sharing a Swedish-language tweet from another "alt-right" supporter saying that Spencer had been banned in Europe because of his views.

It appeared that Spencer addressed attendees remotely.

Mustache Nationalism knows no borders https://t.co/uNyy6HTETo — Richard Spencer (@RichardBSpencer) July 5, 2018

ThinkProgress, citing Swedish media, reported earlier Thursday that Spencer attempted to travel to Sweden to make a surprise appearance at a conference for young white nationalists when he was stopped by Polish authorities during a layover in the country, who told him to return to the U.S.

The Associated Press reported last year that Spencer had been banned from entering 26 European countries. Those countries, which include Poland and Sweden, are part of Europe’s visa-free Schengen area.

Spencer said at the time that he would try to challenge the ban, which is in place for five years, according to the AP.

“I’m being treated like a criminal by the Polish government. It’s just insane,” Spencer said at the time. “I haven’t done anything. What are they accusing me of?”

Spencer, a leader within the “alt-right," is one of the more well-known white nationalists in the U.S.

His website was reportedly taken down by the hosting service GoDaddy last month, and Facebook also removed two Spencer-affiliated pages earlier this year.