The Tates are being held in federal detention following their arrest on Saturday. In the coming weeks, a US district judge will consider whether they meet the conditions for extradition.
A lawyer for the brothers, Joseph McBride, blasted the latest charges as "filth and slander", and said they were being kept in solitary confinement.
"Now they sit in a 5x12 cell as political prisoners on American soil, in SOLITARY CONFINEMENT. Make no mistake about it: they are being punished for daring to exercise their First Amendment Rights," he said on X.
"This is un-American and unconscionable," he said.
On Sunday, McBride said he was confident the extradition request would be denied when they appear in court on Monday.
Prosecutors in Britain said the new charges related to four further victims and were brought after authorities received evidence from Bedfordshire Police in southeastern England.
The charges that span alleged incidents between 2010 and 2017 include rape, assault, trafficking and offences relating to "indecent images of a child and extreme pornography".
The brothers already face previous charges of rape, bodily harm, human trafficking and controlling prostitution for gain relating to three other alleged victims in the UK between 2012 and 2015.
The new allegations are the latest in a long-running international legal saga involving the Tates that has spanned the US, Britain and Romania. The brothers have repeatedly denied wrongdoing.
Their social media empire promoting wealth, male dominance and misogyny has made them among the world's most polarising internet personalities.
The dual US and British citizens moved to Romania in 2016.
They were arrested there in 2022, accused of participating in schemes to lure women for sexual exploitation. They denied those allegations and the Romanian case hasn't gone forward because of legal and procedural problems.
in 2025 they were allowed to leave Romania and flew to Florida.
