The United States government has provided an assurance regarding the treatment of Julian Assange if he was extradited, the WikiLeaks founder’s wife has said.

Assange faces prosecution in the US over an alleged conspiracy to obtain and disclose national defence information following the publication of hundreds of thousands of leaked documents relating to the Afghanistan and Iraq wars.

During a two-day hearing in February, lawyers for the 52-year-old asked for the go-ahead to challenge a judge’s dismissal of the majority of his case to prevent his extradition.

Last month Dame Victoria Sharp and Mr Justice Johnson dismissed most of Assange’s legal arguments but said that unless assurances were given by the United States he would be able to bring an appeal on three grounds.

These assurances are that Assange would be protected by and allowed to rely on the First Amendment – which protects freedom of speech in the US – that he is not “prejudiced at trial” due to his nationality, and that the death penalty is not imposed.

On Tuesday, the deadline for the assurances to be provided, Assange’s wife Stella Assange said the US had provided “blatant weasel words” in response.

She said: “The United States has issued a non-assurance in relation to the First Amendment, and a standard assurance in relation to the death penalty.

“It makes no undertaking to withdraw the prosecution’s previous assertion that Julian has no First Amendment rights because he is not a US citizen.

“Instead, the US has limited itself to blatant weasel words claiming that Julian can ‘seek to raise’ the First Amendment if extradited.

“The diplomatic note does nothing to relieve our family’s extreme distress about his future – his grim expectation of spending the rest of his life in isolation in US prison for publishing award-winning journalism.”

Julian Assange extradition
Stella Assange speaking during a press conference after her husband’s bid for an appeal against extradition to the US was delayed last month (Lucy North/PA)

Judges are now expected to consider the submission from the US authorities, as well as any response from Assange’s lawyers, at a hearing in May.

Mrs Assange also called on the US government to “drop this dangerous prosecution”.

The statement comes after President Joe Biden said the US was “considering” dropping Assange’s prosecution.

Mr Biden told reporters at the White House on April 11 “we’re considering it” when asked about a request from the Australian government to drop the prosecution.

Australian Prime Minister Anthony Albanese has been pressing for Assange’s release for the past few months.

In February, Mr Albanese voted in favour of a motion in the Australian House of Representatives that called on the US and the UK to bring the “matter to a close so that Mr Assange can return home to his family in Australia”, the Associated Press reported.