The United States won an appeal in London's High Court to have Wikileaks founder Julian Assange extradited to face criminal charges, including breaking a spying law and conspiring to hack government computers.
"The court allows the appeal," Judge Timothy Holroyde said.
The judge said he was satisfied with a package of assurances given by the United States about the conditions of Assange's detention including a pledge not to hold him in a so-called "ADX" maximum security prison in Colorado and that he would be transferred to Australia to serve his sentence if convicted.
The ruling brings Assange one step closer to being extradited but further hurdles remain.
Judge Holroyde said the case must now be remitted to Westminster Magistrates' Court with the direction judges send it to the British government to decide whether or not Assange should be extradited to the United States.
US authorities accuse Australian-born Assange, 50, of 18 counts relating to Wikileaks' release of vast troves of confidential US military records and diplomatic cables which they said had put lives in danger.
The United States was appealing against a 4 January ruling by a London District Judge that Assange should not be extradited because he would likely commit suicide in a US prison.
WikiLeaks came to prominence when it published a US military video in 2010 showing a 2007 attack by Apache helicopters in Baghdad that killed a dozen people, including two Reuters news staff. It then released thousands of secret classified files and diplomatic cables.
US prosecutors and Western security officials regard Assange as a reckless and dangerous enemy of the state whose actions imperilled the lives of agents named in the leaked material.
But supporters cast Assange as an anti-establishment hero who has been victimised by the United States for exposing US wrongdoing in Afghanistan and Iraq.