WikiLeaks founder Julian Assange (C) arrives at the High Court in London July 12, 2011. [Photo/Agencies]

LONDON - An attorney for WikiLeaks founder Julian Assange sought on Tuesday to block his extradition to Sweden over sexual assault allegations, arguing that Swedish authorities' case is flawed.

Defense attorney Ben Emmerson said that Assange's case rests on several points - among them that the European arrest warrant issued against him inaccurately described what happened and that, given that the 40-year-old Australian is only wanted for questioning, extraditing him would be disproportionate.

Emmerson, addressing the gathered media, emphasized that he was not trying to denigrate Assange's accusers. But he insisted that Assange's sexual encounters had been "entirely consensual."

Assange's disclosures on WikiLeaks of classified US documents has infuriated the Pentagon, embarrassed US State Department diplomats and energized critics of American foreign policy, while allegations of sexual misconduct during a trip to Scandinavia last year have tarnished his reputation.

Assange denies any wrongdoing, and he and his supporters have suggested that the Swedish prosecution is being manipulated to political ends - possibly with an eye toward sending him to the United States, where a federal grand jury is investigating WikiLeaks' activities.

Swedish authorities reject the charge, and on February 24 a British District Court judge found in their favor, saying there is no reason to believe he wouldn't receive a fair trial in Sweden.

Assange vowed to fight the decision, and meanwhile has continued to work from a wealthy supporter's mansion in eastern England, where he lives under virtual house arrest.

On Tuesday, Assange sat in the second row of the wood-paneled room in a British High Court, flanked by supporters. He wore his platinum-colored hair cut short, with spectacles and a dark-colored suit. Members of public gathered in the court's upper gallery. Outside a small group of protesters were gathered, with one banner reading: "The First Casualty of War is Truth."

In an interview last month, Assange complained that the strict bail conditions - he's under an overnight curfew, must wear an electronic tag and report to police daily - had hampered his activities.

His website has not accepted any new material in months, although WikiLeaks' latest release in April - hundreds of detainee assessment forms covering the inmates at Guantanamo Bay - offered never-before-published information on those being held at the US military prison.

Assange's appeal hearing was due to last until Wednesday. Judgment is expected to be reserved, which means that a ruling might not be made public for days or weeks. Assange has vowed to take his case to Britain's Supreme Court or the European Court of Human Rights if his appeal is rejected.

Online, there were hints from a high-profile member of Anonymous - an amorphous, loosely organized group of hackers sympathetic to WikiLeaks - that confidential US data might be leaked online to coincide with the hearing.