A former British spy who compiled a dossier alleging links between Donald Trump and the Kremlin is asking a US court to throw out a defamation case against him by three Russian oligarchs.
In the legal action filed in Washington DC, Christopher Steele accuses Mikhail Fridman, Petr Aven and German Khan of intimidation.
The oligarchs filed the case on 16 April after their names surfaced in Mr Steele's dossier.
In their lawsuit, the tycoons argue that the dossier was "gravely damaging" because it "falsely accuses Plaintiffs… of criminal conduct and alleged cooperation with the 'Kremlin' to influence the 2016 presidential election".
Mr Steele's file was commissioned by Mr Trump's political enemies before the 2016 election in a bid to dig up dirt on him.
The former British spy's attorney, Christina Eikhoff, told the BBC Russian Service that "the case [against Mr Steele] was filed to punish and intimidate him. Mr Steele is not intimidated."
However, the Steele legal team's court motion says the ex-MI6 officer is concerned for his safety, and fears any public disclosure of his home address could gravely endanger his family.
The oligarchs are also suing Mr Steele's investigative company, Orbis Business Intelligence, for alleged defamation.
A lawyer for the three Russians told the BBC that Mr Steele's defence is "nonsensical".
The trio head the board of AlfaGroup, a Russian investment conglomerate that crops up repeatedly - misspelled as "Alpha Group" - in Mr Steele's dossier.
In their lawsuit, they reject any suggestion of corruption or co-operation with the Kremlin to influence the US presidential election of November 2016.
The three tycoons have previously brought a defamation case against Fusion GPS, the Washington DC-based research company that hired Mr Steele.
They also sued BuzzFeed, which published the Steele dossier in January 2017.
Both those cases are still ongoing.
President Trump has repeatedly dismissed the Steele dossier on Twitter as "fake" and "fraudulent".
Mr Steele's legal team is trying to have the oligarchs' defamation case dismissed by citing precedent law and the first amendment of the US constitution, which guarantees free speech.
They also argue that they are protected by the District of Columbia's anti-SLAPP act, a defence against lawsuits that are filed simply to silence and scare off critics.
In his dossier, Mr Steele said although the relationship between Russian President Vladimir Putin and AlfaGroup "had had some ups and downs, the leading figures in Alpha [sic] currently were on very good terms with PUTIN".
According to Mr Steele's lawyers, his dossier's statements do not amount to defamation and are not provably false.
The court motion also points out that Mr Fridman and Mr Aven lost a defamation case over an article that sought to link AlfaGroup to organised crime and drug-trafficking in the early 1990s.
In that lawsuit back in 2000, the two oligarchs sued the Washington DC-based Center for Public Integrity.
But a judge threw out the legal action in 2005, ruling there was no malice in the publication.
Alan Lewis, a lawyer for the oligarchs, told the BBC: "The idea that we are seeking to punish or intimidate Mr Steele is nonsensical - he is not the victim here.
"Our clients are the victims of false and defamatory statements disseminated by Mr Steele.
"As our complaint alleges, Messrs Fridman, Aven and Khan brought this lawsuit because the allegations about them in the 'Trump Dossier' that Mr Steele peddled to the media are false.
"And because Mr Steele irresponsibly peddled the harmful allegations contained in the Dossier to the media even though he knew at the time that those allegations had not been corroborated."