In this file photo taken on 24 May 2018, former US soldier Chelsea Manning speaks during the C2 conference in Montreal, Canada. Photo: AFP
In this file photo taken on 24 May 2018, former US soldier Chelsea Manning speaks during the C2 conference in Montreal, Canada. Photo: AFP

Former US Army intelligence analyst Chelsea Manning will remain in jail after a federal appeals court on Monday denied her request to be released on bail, and upheld a lower court's decision to hold Manning in civil contempt for refusing to testify before a grand jury.

The ruling is a blow to Manning, who has been detained since March after she declined to answer questions in connection with the government’s long-running investigation into Wikileaks and its founder Julian Assange.

In a comment released by a spokesman, Manning said that while disappointing, the appeals court ruling will still allow her to "raise issues as the government continues to abuse the grand jury process."

"I don't have anything to contribute to this, or any other grand jury," Manning added.

Assange was arrested on 11 April at Ecuador's Embassy in London, after US prosecutors in the Eastern District of Virginia unsealed a criminal case against him alleging he conspired with Manning to commit computer intrusion.

The Justice Department said Assange was arrested under an extradition treaty between the United States and Britain.

The US government alleges that Assange tried to help Manning gain access to a government computer as part of a 2010 leak by WikiLeaks of hundreds of thousands of US military reports about the wars in Afghanistan and Iraq and American diplomatic communications.

It is not clear if the alleged collaboration between Manning and Assange led to a successful intrusion into any US government computer.

Assange plans to fight the US extradition request. Such cases, when challenged, can take years before they are resolved.

Manning was convicted by court-martial in 2013 of espionage and other offenses for furnishing more than 700,000 documents, videos, diplomatic cables and battlefield accounts to WikiLeaks while she was an intelligence analyst in Iraq.

Former US president Barack Obama, in his final days in office, commuted the final 28 years of Manning’s 35-year sentence.

Manning has tried to fight the grand jury subpoena in the Assange case, citing her First, Fourth and Sixth Amendment rights under the Constitution.

Manning's lawyer, Moira Meltzer-Cohen, suggested prosecutors were abusing "grand jury power," and that "the likely purpose of her subpoena is to help the prosecutor preview and undermine her potential testimony as a defence witness for a pending trial."

Her lawyers have also argued that the courtroom was improperly sealed during substantial portions of the hearing.

But a three-judge panel of the US Court of Appeals for the Fourth Circuit did not agree with those claims.

"The court finds no error in the district court’s rulings and affirms its finding of civil contempt," they wrote.