Andrew Tate, the wealth-flaunting online influencer known for his misogynistic views, and his brother, Tristan, were taken into custody Monday night in Romania on a European arrest warrant issued by the British authorities, a spokesman for Mr. Tate said.

The charges related to the arrest were made between 2012 and 2015 and include allegations of sexual aggression, the spokesman said. He added that the charges had been dismissed by the Crown Prosecution Service years later.

The local police in Romania said in a brief statement that the arrest warrants were for sexual crimes and the exploitation of individuals in Britain. The men were also ordered detained for 24 hours, it said.

It is unclear which British force issued the warrant or why the case has been reopened.

The Bucharest Court of Appeal in Romania is expected to make a decision Tuesday afternoon on whether to extradite the Tate brothers to Britain, Mr. Tate’s spokesman said.

The spokesman said the brothers “categorically reject all charges and express profound disappointment that such serious allegations are being resurrected without substantial new evidence.”

Mr. Tate, who regularly uses various platforms to broadcast his virulent brand of male chauvinism, posted on social media Tuesday morning, “The Matrix is afraid, but I only fear God.”

Mr. Tate, a former professional kickboxer, and his brother were separately charged in 2022 with forming an organize criminal group and engaging in human trafficking across Romania, Britain and the United States.

Some details of those charges have been kept confidential, but an official in the prosecutor’s office in Romania confirmed that Mr. Tate was also facing accusations of rape in the 2022 case. The brothers have denied the accusations against them and maintain their innocence.

It was not immediately clear when a trial in that case would begin.

Mr. Tate’s profile grew after he appeared as a contestant on the British reality show “Big Brother” in 2016. He was kicked off the show, according to The Sun tabloid, after a video surfaced of him hitting a woman with a belt, which he and the woman said was consensual.

He later amassed millions of followers, many of the young men, by claiming that men are victims of feminism and that women “belong” to men and need men’s guidance.

Because Mr. Tate’s views have reached so many school-aged boys, education officials across Britain have been scrambling to mitigate his influence. In fact, some are using class time to discuss Mr. Tate.

Matei Barbulescu contributed reporting from Romania.