London (CNN) -- WikiLeaks founder Julian Assange, under house arrest in Britain for more than a year, appeared at the UK Supreme Court on Wednesday to fight his extradition to Sweden.
His lawyers argued a Swedish warrant for Assange's arrest is invalid because it was issued by a Swedish prosecutor, who they say is not an independent and impartial judicial authority.
The warrant is an effort to bring Assange to Sweden to face questioning about accusations, unrelated to WikiLeaks, that he sexually assaulted two women in 2010. Assange has not been charged with a crime and has denied wrongdoing.
The prosecution is expected to make its case at the Supreme Court on Thursday; a decision is not expected for weeks.
Assange, who made no statement Wednesday, has been living at the Suffolk country mansion of one of his supporters since December 2010. He lost a court battle last November against extradition, but the High Court ruled in December that he could appeal.
Assange's lawyers have vowed to take their fight all the way to the European Court of Human Rights if necessary.
The extradition case is not linked to Assange's work as founder and editor-in-chief of WikiLeaks, which has put him on the wrong side of U.S. authorities.
The organization, which facilitates the anonymous leaking of secret information, has published some 250,000 confidential U.S. diplomatic cables, causing embarrassment to the government and others.
It has also published hundreds of thousands of classified U.S. documents relating to the conflicts in Iraq and Afghanistan.
But the organization has come under increasing financial pressure in recent months, leading Assange to announce in October that WikiLeaks was temporarily stopping publication to "aggressively fundraise" in order to stay afloat.
While Assange waits for the Supreme Court to rule on his extradition, he plans to host a talk show on Russian TV. The Alyona Show, which appears on the Kremlin-funded, pro-Russian network Russia Today, said Wednesday that Assange will conduct interviews from the Suffolk mansion, with an electronic bracelet monitoring his movements.
Assange will also voice a character in an upcoming episode of the animated series "The Simpsons," the magazine Entertainment Weekly reported Wednesday.
CNN's Atika Shubert contributed to this report.