What did he do and what are they accusing him of?
The United States indicts Assange on 18 counts, including hack from US military databases to acquire secret sensitive information related to the wars in Afghanistan and Iraq which he later published on the Wikileaks website.
The Australian maintains that the information exposed abuses perpetrated by the US armed forces.
If convicted in the United States, Assange would face a 175-year prison sentence, his lawyers say.
However, the US government has said the sentence would most likely be between four and six years.
On August 21, 2010, following instructions from the Swedish police, the prosecutor Maria Häljebo ordered the arrest of Assange accused of the rape of Anna Ardin, linked to the Cuban opposition. The prosecutor withdrew the accusation a few hours later stating that there had been no grounds to suspect that he was involved in a rape.
In September 2010, the Swedish superior prosecutor, Marianne Ny, considered that there were reasons to believe that the crime had been committed and that it should be classified as rape and consequently ordered the reopening of the preliminary investigation against Assange for an alleged crime of rape.
Julian Assange has two arrest warrants in Sweden for alleged crimes of, respectively, rape in the case of Anna Ardin and sexual harassment in the case of Sofia Wilen. He is accused above all of having forced one of the alleged victims to have sexual intercourse in his sleep, without using a condom.
He is also suspected of sexually assaulting another woman for refusing to put on a condom contrary to her express wish. And sexual assault on the sexual integrity of this woman, as well as illegal coercion for having used the full weight of her body on her during one of her sexual relations.