A federal appeals court denied on Monday a request by former U.S. Army intelligence analyst Chelsea Manning to be released from jail 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 marks a blow for 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.

Neither a spokesman for Manning nor Manning's attorney could not be immediately reached for comment.