London, UK - WikiLeaks founder Julian Assange, accused by the US of leaking state secrets, has been denied permission to appeal against a British High Court's December decision to extradite him to the United States, the Supreme Court confirmed on Monday.

Britain's highest court said that senior judges had refused Assange's bid to challenge the decision, as his application did not raise "an arguable point of law."

However, Assange's legal team previously said there were other parts of his appeal that had not yet been heard by the High Court.

The 50-year-old is wanted in the US for alleged conspiracy to obtain and disclose national defense information following WikiLeaks' publication of hundreds of thousands of leaked documents relating to the Afghanistan and Iraq wars.

US authorities brought a High Court challenge against a January ruling, by then-district judge Vanessa Baraitser, that Assange should not be sent to the US, in which she cited a real and "oppressive" risk of suicide.

After a two-day hearing, the Lord Chief Justice Lord Burnett, sitting with Lord Justice Holroyde, ruled in favor of the US. The senior judges found that Baraitser had based her decision on the risk of Assange being detained in highly restrictive prison conditions if extradited.

Yet, the US authorities later gave assurance that Assange would not face strict measures, either pretrial or post-conviction, unless he committed an act in the future that required them.

Burnett previously said that, if the original judge had been given those assurances at the time of her ruling, "she would have answered the relevant question differently."

The WikiLeaks founder's lawyers had sought to appeal against that decision at the Supreme Court, arguing it raises "serious and important" legal issues.

In January, Burnett, sitting with Holroyde, refused permission for the appeal, adding that the decision of whether to hear the appeal was up to the Supreme Court.

In her January 2021 ruling blocking the extradition, Baraitser found in favor of the US on all issues except Assange's mental health. Assange has previously indicated that he wants to challenge the original judge's other findings.

If Assange is extradited and tried in a US court, he faces a possible prison sentence of up to 175 years.