An appellate court in the United Kingdom on Friday allowed WikiLeaks founder Julian Assange to be extradited to the United States for facing criminal proceedings, the BBC reported.

Assange faces 18 charges in the United States in connection with 5 lakh secret files on American military campaigns in Afghanistan and Iraq, released between 2010 and 2011. He is also accused of soliciting and publishing such information.

Assange is currently lodged in London’s Belmarsh Prison.

The High Court in London on Friday overturned a lower court’s verdict holding that the extradition would be “oppressive by reason of mental harm”. It ruled that the United States government’s assurances were sufficient to guarantee that Assange would be treated in a humane manner.

“There is no reason why this court should not accept the assurances as meaning what they say,” the court said, according to AP. “There is no basis for assuming that the USA has not given the assurances in good faith.”

The British appellate court ordered a lower court to send the extradition request to the home secretary for review. The home secretary will take the final decision on Assange’s extradition.

The WikiLeaks founder’s supporters had gathered outside the court, holding banners seeking his release.

Assange’s fiancé Stella Morris said that their lawyers will file an appeal against the ruling “at the earliest possible moment”. She called the decision a “grave miscarriage of justice”.

Assange has been in the Belmarsh Prison since April 2019, after he was removed from the Ecuadorian embassy in London, where he took refuge for seven years to avoid extradition to Sweden.

In November 2019, 60 doctors wrote to British Home Secretary Priti Patel saying that Assange’s health had deteriorated so much that he might die in prison.

The WikiLeaks founder was jailed after skipping bail in 2012 to avoid extradition to Sweden, where he was facing a rape investigation. The rape charges were dropped in November 2019.