On June 17, UK Home Secretary Priti Patel approved the extradition of Assange to the United States, where he is facing a possible sentence of up to 175 years in prison. WikiLeaks called Patel's decision a dark day for press freedom and for British democracy and promised to challenge the order.
"Julian Assange is filing his Perfected Grounds of Appeal before the High Court of Justice Administrative Court. The Respondents are the Government of the United States and the Secretary of State for the Home Department, Priti Patel," WikiLeaks said in a statement.
According to the statement, the filed document will contain important new evidence but there was no elaboration on what that might be.
"Since the last ruling, overwhelming evidence has emerged proving that the United States prosecution against my husband is a criminal abuse. The High Court judges will now decide whether Julian is given the opportunity to put the case against the United States before open court, and in full, at the appeal," Julian Assange's wife Stella Assange said.
Assange is wanted by the US on espionage charges after WikiLeaks published thousands of classified documents that shed light on war crimes committed by American troops in Iraq and Afghanistan.