Assange had been residing at the Ecuadorian Embassy in London for nearly seven years before his asylum was revoked on 11 April, followed by his arrest and further extradition to the Westminster Magistrate's Court.

Julian Assange's lawyers have filed a lawsuit against a group of Spaniards, members of staff at the Ecuadorian Embassy in London, as well as Ecuador's Foreign Ministry over extortion, AFP reported, citing Assange's defence team.

Earlier, Spanish media reported that the group of Spaniards had got hold of Assange's videos and personal documents, which they threatened to publish unless paid $3.3 million by the WikiLeaks team.

The lawsuit was reportedly brought forward in Spain. The source also noted that an investigation into the matter was ongoing, adding that Assange was allegedly spied on in the embassy. However, the source failed to provide evidence or further details.

READ MORE: UN Expert Says Concerned Assange Faced at Least 2 Forms of Privacy Infringement

Assange, the founder of the whistleblowing website WikiLeaks, was caught in the lens of the general public after his website published a large trove of classified documents, including some that exposed abuses of power and war crimes committed by US troops in Afghanistan and Iraq, as well as at the Guantanamo Bay detention camp.

In 2012, Assange sought refuge in the Ecuadorian Embassy to avoid extradition to Sweden over allegations of sexual assault.

The WikiLeaks whistle-blower had been residing at the Ecuadorian Embassy in London for almost seven years before his asylum was revoked, leading to his arrest by UK police for jumping bail in Westminster Magistrate's Court.

The next hearing in Assange's case is set to take place on 2 May.