Supporters of Wikileaks founder Julian Assange celebrate outside the Old Bailey court in London after a judge ruled that Assange should not be extradited to the United States to face espionage charges for publishing secret documents online on Monday. Photo: AFP

Lawyers for WikiLeaks founder ­Julian Assange argued Wednesday he should be released from a British prison on bail, pending Washington's appeal against a decision not to extradite him to the US.

A judge in London on Monday blocked his extradition to face charges for publishing hundreds of thousands of secret documents online, assessing he was a high suicide risk if transferred.

The United States, which called the ruling "extremely disappointing," has said it will appeal, and has two weeks to lodge its grounds.

Assange has remained in the high-security Belmarsh prison in southeast London pending the latest hearing, at Westminster Magistrates' Court in central London.

The 49-year-old Australian publisher's long-running legal woes have become a cause celebre for media freedom, despite the judge's view he had a case to answer in the US.

A previous bail hearing in March was told he should be released because he was vulnerable to COVID-19 while behind bars. The argument was rejected on the grounds he was likely to abscond.

He was arrested in 2019 after seeking sanctuary at Ecuador's Embassy in London in 2012 following Sweden's issuing of an arrest warrant in connection with sexual assault allegations.

British police dragged Assange out of the embassy in April 2019 after Ecuador revoked his citizenship. He was arrested for breaching his bail terms in connection with the Swedish case, which was later dropped due to lack of evidence, and sentenced to 50 weeks, which the UN called "disproportionate." 

He has remained at Belmarsh pending the conclusion of the American extradition request. 

Assange is still wanted on 18 charges in the US - bearing a maximum 175-year sentence - relating to the 2010 release by WikiLeaks of 500,000 secret files detailing aspects of military campaigns in Afghanistan and Iraq.

Washington claims he helped intelligence analyst Chelsea Manning steal the 2010 documents before exposing confidential sources around the world.

Assange and his lawyers have long argued that the protracted case is ­politically motivated.