WikiLeaks founder Julian Assange, who has been in hiding for nearly a week, was arrested here today on suspicion of rape after surrendering over a Swedish warrant, a move described as an attack on the freedom of press by his whistle-blower website that has leaked a cache of secret US cables.

39-year-old Assange, an Australian citizen, was arrested by the Metropolitan police on the basis of an arrest warrant issued from Sweden relating to allegations of sexual assaults against him.

The elusive WikiLeaks founder and Editor-in-Chief has denied allegations that he sexually assaulted two women in Sweden.

In a statement, police said: "Officers from the Metropolitan Police Extradition Unit have this morning arrested Julian Assange on behalf of the Swedish authorities on suspicion of rape."

Assange "was arrested on a European Arrest Warrant by appointment at a London police station at 9.30 am. He is accused by the Swedish authorities of one count of unlawful coercion, two counts of sexual molestation and one count of rape, all alleged to have been committed in August 2010."

Soon after he was taken into custody, a spokesman for WikiLeaks said the arrest will not stop the release of more secret files.

He said Assange's arrest -- which took place amid release of a series of classified US government cables -- was an attack on the freedom of press.

The extradition of Assange, who was due to appear at City of Westminster Magistrates' Court later today, may take a long time due to legal challenges, but it can be swift if the accused waives his legal rights.

Assange's supporters have written an open letter to Australian Prime Minister Julia Gillard, asking her to protect him.

One of the signatories, prominent barrister, Julian Burnside said: "First and foremost Julian Assange is an Australian citizen who is entitled to the protection of his country and does not deserve to be betrayed by his country."

"Julia Gillard has been making it virtually impossible for Assange to return to Australia where he is entitled to be.

And she has even threatened to cancel his passport. That is an outrageous stance to take."

Mark Stephens, a lawyer representing Assange, said: "He has not been charged with anything. It's about time we got to the end of the day and we got some truth, justice and rule of law."

In Sweden, a WikiLeaks spokesman called for action against those who have attacked Assange.

"There have been death threats to his life and incitement to murder," he added.