WikiLeaks founder Julian Assange was denied bail in a British court on Tuesday and will remain behind bars after saying he plans to fight extradition to Sweden, where he faces sex charges.

In handing down his decision in the City of Westminster Magistrates' Court in London, Judge Howard Riddle said he had "substantial grounds" to believe Assange would not appear for his next hearing, slated for Dec. 14.

tp-wikileaks-assange-rtxu7g3

Julian Assange surrendered in the U.K. and is being held until his next court appearance Dec. 14.

The 39-year-old Australian was arrested Tuesday morning after he voluntarily appeared for an appointment at a London police station. 

In his afternoon appearance at the court, where a group of supporters had gathered, Assange was asked whether he understood that he could consent to be extradited to Sweden. He replied he understood and would not consent, The Associated Press reported.

Assange is accused by Swedish authorities of one count of rape, one count of unlawful coercion and two counts of sexual molestation alleged to have been committed in August, police said.

P.O.V.:

Do you believe WikiLeaks is good for democracy? Take our survey.

Mark Stephens, Assange's London-based lawyer, has said the charges stem from a "dispute over consensual but unprotected sex".

After Tuesday's hearing, Stephens said a renewed application for bail for Assange is expected to be made, but he said no decision has been made on when that will occur.

Asked by reporters in a scrum about Assange being held, Stephens said: "I'm sure the British judicial system is robust enough not to be interfered with by politicians, and that our judges are impartial and fair, and that our prosecutors are also impartial and fair. I hope that I can say same the same thing about Swedish prosecutors at some point in the future."

The founder of the whistleblowing website that has released reams of sensitive U.S. diplomatic cables has denied the allegations.

The WikiLeaks founder had been hiding out at an undisclosed location in Britain since the website began publishing the controversial diplomatic cables.

Kristinn Hrafnsson, a spokesman for WikiLeaks, said Assange's arrest is an attack on media freedom, adding that the arrest won't stop the organization from releasing more documents online.

"This will not change our operation," he told The Associated Press.

Assange has said the documents will be released no matter what happens to him.

tp-mark-stephens-cp-9866365

Mark Stephens, lawyer for whistleblowing website WikiLeaks founder Julian Assange, speaks to the media as he arrives at City of Westminster Magistrates' Court in London on Tuesday. ((Kirsty Wigglesworth/Associated Press))

His lawyer has criticized Swedish prosecutor's handling of the case, saying his client has never been fully informed of the details of the allegations against him.

Marianne Ny, the Swedish prosecutor handling the case, has denied the investigation is politically motivated.

The organization's room to manoeuvre is narrowing by the day. It has been battered by web attacks, cut off by internet service providers and is the subject of a criminal investigation in the United States, where officials say the release jeopardized national security and diplomatic efforts around the world.

The campaign against WikiLeaks began with an effort to jam the website as the cables were being released. U.S. internet companies Amazon.com, Inc., EveryDNS and PayPal, Inc. then severed their links with WikiLeaks in quick succession, forcing it to jump to new servers and adopt a new primary web address — wikileaks.ch — in Switzerland.

Swiss authorities closed Assange's new Swiss bank account Monday, and MasterCard has pulled the plug on payments to WikiLeaks, according to technology news website CNET. Visa followed on Tuesday, saying it has suspended all payments to WikiLeaks "pending further investigation."

With files from The Associated Press