Assange has been remanded into UK custody until Dec. 14.
Despite Assange's legal troubles, a WikiLeaks spokesman insisted the flow of secret U.S. diplomatic cables would not be affected. He also downplayed efforts to constrict the group's finances after both Visa and MasterCard cut off key funding methods Tuesday.
As if to underline the point, WikiLeaks released a dozen new diplomatic cables, its first publication in more than 24 hours, including the details of a NATO defense plan for Poland, Estonia, Latvia and Lithuania that prompted an indignant response from the Russian envoy to the alliance.
The 39-year-old Australian turned himself in to Scotland Yard on Tuesday morning and appeared at Westminster Magistrate's Court, telling the court he will fight extradition.
Two women Assange met in Sweden over the summer have accused the Australian of rape in one case and sexual molestation and unlawful coercion in the other.
Assange's attorney Mark Stephens said the allegations stem from a "dispute over consensual but unprotected sex," and has suggested the prosecution is manipulated for political reasons.
Since releasing hundreds of secret U.S. diplomatic cables, WikiLeaks has faced legal, financial and technological challenges. Its bank accounts were canceled, its websites attacked and the U.S. has launched a criminal investigation.
The Associated Press contributed to this story.