Chelsea Manning must stay in jail on contempt of court for refusing to testify before a grand jury investigating WikiLeaks' Julian Assange, an appeals court ruled Monday.

Assange, founder of the anti-secrecy website, was charged under seal in Alexandria federal court last year with conspiring to help Manning break a Defense Department password. The case was made public when he was arrested in London earlier this month. But prosecutors are still investigating and may file more charges before moving forward with an extradition request. In court filings, Manning has said she believes they want to undermine her potential testimony as a defense witness.

"The court finds no error in the district court's rulings and affirms its finding of civil contempt," a three-judge panel for the Fourth Circuit Court of Appeals wrote in a brief order. The panel also rejected Manning's bid to be let out of jail while she fights the subpoena. She can still appeal to the full Fourth Circuit or Supreme Court.

Attorneys for Manning declined to comment before speaking with her.

Manning, a former Army intelligence analyst, has admitted that she leaked hundreds of thousands of classified government documents to Assange in 2010. She served seven years in prison before her sentence was commuted by former President Barack Obama.

In March, Manning was called before a federal grand jury in Alexandria investigating Assange and jailed for declining to answer questions.

Manning has argued that she acted alone and simply chose WikiLeaks as the vehicle for the State Department cables, war logs and Guantanamo detainee reports she wanted to make public. Prosecutors in Alexandria dispute that characterization, saying her relationship with Assange went further. In a recently unsealed complaint, they note that while Manning told a military judge she was never sure she was actually speaking to Assange, she told an FBI informant she had confirmed the WikiLeaks founder's identity.

