LONDON－WikiLeaks' founder Julian Assange on Friday moved a step closer to facing criminal charges in the United States for breaking spying law and conspiring to hack government computers after Washington won an appeal over his extradition in an English court.

The High Court in London ruled that US assurances were enough to guarantee Assange would be treated humanely and directed a lower court judge to send the extradition request to the home secretary for review. The home secretary, who oversees law enforcement in the UK, will make the final decision on whether to extradite Assange.

"There is no reason why this court should not accept the assurances as meaning what they say," the High Court ruling stated.

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.

Supporters cast Assange as an anti-establishment hero who has been victimized by the US for exposing US wrongdoing in Afghanistan and Iraq.

The US won an appeal against a ruling by a London District Judge that Assange should not be extradited because he would likely commit suicide in a US prison.

"The court allows the appeal,"Judge Timothy Holroyde said.

The judge said he was satisfied with a package of assurances given by the US 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.

But further hurdles remain before Assange can be sent to the US: the legal wrangling is likely to go to the Supreme Court, the final court of appeal.

Assange's fiance, Stella Moris, said his legal team would appeal the decision.

"How can it be fair, how can it be right, how can it be possible, to extradite Julian to the very country which plotted to kill him?" she said. "We will appeal this decision at the earliest possible moment."

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.

Assange, who denies any wrongdoing, was not in court. He remains in London's high-security Belmarsh prison, where he has been for more than two and a half years.

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 imperiled the lives of agents named in the leaked material.

His admirers have hailed Assange as a hero for exposing what they describe as abuse of power by modern states and for championing free speech.

AGENCIES VIA XINHUA