Events will be held across the world today to mark the 1000th day spent in prison by the US soldier arrested over the leaking of classified documents to the whistleblowing website WikiLeaks.

Private Bradley Manning was arrested in May 2010 in Iraq. A court martial is due to be held in June at Ford Meade in Maryland, with supporters treating him as a hero but opponents calling him a traitor.

A series of protests and demonstrations will be held across the United States and Europe, including in London, Yorkshire and Cardiff.

"There has never been a more important time to broadcast our message of support for exposing war crimes, international justice, and people's right to know what the government does in our name," said a spokesman for a Bradley Manning campaign group in the US.

WikiLeaks founder Julian Assange has been in the Ecuadorian Embassy in London since last June. He is seeking to avoid extradition to Sweden, where he faces allegations of sex offences, which he denies. He fears being sent to the US if he travels to Sweden.

New York civil rights attorney Chase Madar has written a book about Manning, raising a number of issues including the soldier's solitary confinement for 11 months after his arrest.

Mr Madar said most people in the US did not know who Manning was, and only a minority would regard him as a national hero. He added: "I believe what he did was a good thing, both for the United States and for the rest of the world."