Hundreds of Julian Assange supporters have rallied in London as his lawyers urged the UK's interior minister to block his extradition.
Last month, a court in the United Kingdom issued a formal order to extradite WikiLeaks founder Julian Assange to the United States, where he could face a lifetime in prison on espionage charges.
Assange's lawyers appeared to have met a Wednesday deadline to make representations to the British interior minister, and could also potentially launch further appeals on other points in the case.
"Defence submissions to Home Secretary Priti Patel have just been filed, arguing why the US extradition of Assange must be blocked," his wife, Stella Moris, said on Twitter several hours before the protest outside Patel's ministry.
Assange supporters denounced Washington policy as a great threat to freedom of the press.
WikiLeaks editor-in-chief Kristinn Hrafnsson told AFP on the sidelines of the demonstration that Assange had "suffered enough" after being "deprived of freedom for more than a decade."
"He is heartened by the fact that he notices that the general public and politicians as well around the world are rallying to his support," Hrafnsson added.
Protester Amaru Narvaez-Reyes, a 25-year-old actor, said Assange's extradition to the United States "would be very damning for the freedom of the press."
"It would put fear into the hearts of a lot of journalists and probably prevent a lot of important information to come to the public eye," he told AFP.
The Australian-born journalist, who has denied all accusations against him, has been held in a British prison for over 36 months. Before that, he spent seven years holed up at the Ecuadorian Embassy in London, under threat of arrest by the UK authorities.
Assange says he had merely engaged in investigative journalistic activities that are legal in the US, and that accusations of him conspiring to hack the Pentagon's computer systems were false. He and his supporters believe the accusations are politically motivated and "represent an unprecedented attack on press freedom and the public's right to know - seeking to criminalize basic journalistic activity."