WikiLeaks founder Julian Assange asked a British judge on Monday to block his extradition to Sweden on sex crime allegations, arguing he would not get a fair trial and could end up facing execution in the United States.

The 39-year-old Australian computer expert, who has infuriated the U.S. government by releasing thousands of secret U.S. diplomatic cables on his website, is wanted in Sweden where two WikiLeaks volunteers allege sexual misconduct last August.

His lawyers argued on the first day of a two-day extradition hearing that Assange should not be sent to Sweden because rape cases there are held in private and so Assange would be denied a fair trial.

Assange, who has been free on bail under strict conditions since December, said at the end of the day he was confident the hearing would dispel the rape allegations hanging over him.

For the past five-and-a-half months, we have been in a condition where a black box has been applied to my life. On the outside of that black box has been written the word 'rape'. That box is now, thanks to an open court process, being opened, he told reporters massed outside the maximum-security Belmarsh magistrates' court in southeast London.

Assange's lawyer Geoffrey Robertson told the court earlier that there was a real risk of flagrant violation of his rights if he were sent to Sweden because most rape trials there are held behind closed doors.

DEATH PENALTY

In a 74-page court submission, Assange's lawyers argue there is a risk that, if he was extradited to Sweden, the United States would seek his extradition and/or illegal rendition to the USA, where there will be a real risk of him being detained at Guantanamo Bay.

If he was sent to the United States, there was a risk he could be made subject to the death penalty on charges of espionage for publishing the diplomatic cables.

Prosecution lawyer Clare Montgomery said there was no proof that Assange ran the risk of being extradited to the United States and, if it did happen, Britain would have to give its consent first.

Montgomery dismissed defense arguments that Swedish prosecutors were abusing the fast-track European arrest warrant process because they only want to question Assange and have not yet decided whether to prosecute him.

Retired Swedish appeal court judge Brita Sundberg-Weitman, called as a defense expert witness, attacked Marianne Ny, the Swedish director of public prosecutions who is seeking to extradite Assange, accusing her of having a rather biased view against men. Swedish media were hostile to Assange, she said.

A second defense witness, Goran Rudling, a 59-year-old campaigner for reform of Swedish sex crimes laws, said one of Assange's accusers, known as Miss A, had later deleted several tweets she had sent on the day after Assange's alleged crime suggesting that she was happy to be in his company.

It seemed obvious that the story told to the police and these facts just didn't go together, he said.

Grounds for refusing an extradition request are mainly limited to whether it would violate a suspect's human rights or whether the arrest warrant was drawn up correctly.

The U.S. government is examining whether criminal charges can be brought against him over the diplomatic cables.

Lawyer Gemma Lindfield, representing Swedish judicial authorities, told an earlier court hearing in London that the extradition case contained allegations of four sexual assaults by Assange against two women in Stockholm in August 2010.

(Editing by Jon Hemming)

United kingdom Wikileaks Julian Assange