NEW YORK - US-based lawyers for Julian Assange are suing the CIA and former US secretary of state Mike Pompeo for allegedly covertly monitoring the WikiLeaks founder and his visitors when he was holed up in the Ecuadorian embassy in London.

Assange spent seven years in the Knightsbridge embassy in an attempt to evade extradition to Sweden where he faced charges of sexual assault.

During those years he entertained guests – many of them celebrities – and also met with his lawyers and with journalists. He fathered two sons with his now wife Stella, which he managed to keep secret from the rest of the world.

Assange is now being held in HM Belmarsh Prison where he is appealing his extradition to the United States to face charges under the Espionage Act relating to the theft and publication of hundreds of thousands of secret diplomatic cables.

The extradition process underway in British courts has heard sensational evidence that a Spanish firm, Undercover Global, was hired by the CIA – headed by Pompeo at the time – to covertly monitor Assange inside the embassy.

Legal proceedings in Spanish courts against the head of that firm, David Morales, heard testimony in 2020 that Assange’s visitors had the data on their phones copied unknowingly when they were required to hand over their belongings to Morales’ staff.

At a press conference in New York on Monday, Assange’s US lawyers said the suit alleges that unbeknown to even the Ecuadorians, who granted Assange aslyum, the data on their phones and other electronic devices was copied and handed over to the CIA.

Assange’s lawyers argue that more than 100 US citizens, including journalists who visited Assange during his years in the embassy, had their constitutional rights violated.

“It’s very outrageous conduct,” said Richard Roth, whose firm Roth Law Firm is representing the group that brought the lawsuit, which was filed in the United States southern district of New York’s District Court.

The plaintiffs are US attorneys Margaret Ratner Kunstler, Deborah Hrbek, German-based US journalist John Goetz and the UK-based American journalist Charles Glass.

Roth said the suit was being brought under the US constitution’s Fourth Amendment which he said applied to American citizens regardless of which country they were in at that time.

The amendment protects citizens against unreasonable searches and seizures carried out by the government.

Roth said they were suing potential 2024 presidential contender Pompeo as a personal citizen, citing a precedent that allows for lawsuits to be brought against former directors of the CIA in their personal capacity.

He predicted the case would take about 12 months.

Critics of Assange’s incarceration, including Labor MPs in the Australian government, say that an Australian citizen should not be extradited from a third country to another third country.

The CIA, which declined to comment on the lawsuit, is prohibited from collecting intelligence on U.S. citizens, although several lawmakers have alleged that the agency maintains a secret repository of Americans’ communications data.

Legal experts, including a former senior intelligence official, told Newsweek that the allegations in the lawsuit, if proven, show the CIA crossed lines drawn to protect American citizens from surveillance by overzealous intelligence agencies.