Andrew Tate and his brother Tristan were seen arriving at a Romanian court in handcuffs as they appealed their 30-day detention.
The brothers were arrested by police investigating charges of human trafficking and organized crime.
Both brothers deny any wrongdoing and have challenged their arrest.
Andrew Tate is a former kickboxer and influencer who has 4.4 million followers on Twitter. He and his brother were detained on December 29.
According to prosecutors, the Tate brothers exploited female victims by forcing them to produce sexually explicit content for social media.
Romania’s anti-organized crime agency, DIICOT, said that it had identified six victims in the case who were subjected by the group to “acts of physical violence and mental coercion” and were sexually exploited by group members.
The agency said victims were lured by pretences of love, and later intimidated and subjected to other controlling tactics into performing acts intended to reap substantial financial gains.
The judge who ordered the detention of the brothers said “the possibility of them evading investigations cannot be ignored” and that they could “leave Romania and settle in countries that do not allow extradition”.
If the court upholds the arrest warrant extension on Tuesday, prosecutors could request detention for a maximum of 180 days.
If the court overturns the extension, the defendants could be put under house arrest or similar conditions such as being banned from leaving Romania.
Tate, who is reported to have lived in Romania since 2017, has previously been banned from various prominent social media platforms for expressing misogynistic views and hate speech.
Prosecutors have seized a total of 15 luxury cars, of which at least seven are owned by the Tate brothers, and more than 10 properties or land owned by companies registered to them, said Ramona Bolla, a spokesperson for DIICOT.
She said that if prosecutors can prove they gained money through human trafficking, the property “will be taken by the state and (will) cover the expenses of the investigation and damages to the victims”.
Two Romanian suspects are also in custody and have challenged the arrest extension that was granted to prosecutors on December 30.
Since Tate’s arrest, a series of ambiguous posts have appeared on his Twitter account, each of which garners widespread media attention.
One, posted on Sunday and accompanied by a local report suggesting he or his brother have required medical care since their detention, reads: “The Matrix has attacked me. But they misunderstand, you cannot kill an idea. Hard to Kill.”
Another post, that appeared Saturday, reads: “Going to jail when guilty of a crime is the life story of a criminal … going to jail when completely innocent is the story of a hero.”
A verdict on the appeal is expected later today. Andrew Tate and his brother Tristan were seen arriving at court in handcuffs as they appealed their 30-day detention.
Both deny any wrongdoing and have challenged their arrest.
Prosecutors claim that the brothers exploited female victims by forcing them to produce sexually explicit content for social media.
Andrew Tate is a former kickboxer and divisive influencer who has 4.4 million followers on Twitter and was detained on December 29 with his brother Tristan.