If the UK extradites Julian Assange to the US, the decision would have "serious consequences for press freedom around the world," Reporters Without Borders (RSF) Germany Executive Director Christian Mihr said on Thursday.

The activists called on the UK to release the imprisoned whistleblower while also demanding that US President Joe Biden's administration drop the charges against him.

The statement comes after Britain's High Court earlier this week agreed to hear a US appeal on the decision barring his extradition. The 50-year-old founder of WikiLeaks could face a sentence of 175 years if convicted in the US.

What did RSF say about the Assange case?

Mihr said it was "no surprise" that Britain's High Court moved forward with the US appeal on Assange's extradition. 

"Julian Assange should not be in this position in the first place," Mihr said in a statement.

WikiLeaks' publication of sensitive military and intelligence documents has led US prosecutors to indict Assange on 17 spying charges and one charge of computer misuse. 

Mihr said RSF, along with 23 other organizations, "demand that the Biden administration drop its appeal and close the case."

In January, a British judge ruled that Assange cannot be extradited to the US, saying he would likely commit suicide if held under the harsh American prison system.

Assange's fiance speaks out

Assange's fiance, Stella Moris, also called on the Biden administration to drop the charges this week. 

"I am appealing directly to the Biden government to do the right thing, even at this late stage," Moris said Wednesday. "This case should not be dragged out for a minute longer. End this prosecution, protect free speech and let Julian come home to his family."

Moris has two children with Assange, with the couple intending to marry while he is in prison. 

Assange has spent over two years in London's high-security Belmarsh prison, and recently marked his 50th birthday on July 3 behind bars. He was arrested by London Metropolitan Police in April 2019 for skipping bail.

The WikiLeaks founder previously spent seven years in Ecuador's London Embassy from 2012 to 2019. Assange was in hiding to avoid extradition to Sweden, where he previously faced sexual assault and rape charges. 

Swedish authorities dropped the Assange rape investigation in 2019.