Chelsea Manning, the soldier imprisoned for sending classified information to the anti-secrecy website WikiLeaks was briefly hospitalized this week, the U.S. Army confirmed Wednesday without providing details.

Chelsea Manning was taken to a hospital near Fort Leavenworth early Tuesday and returned to the Kansas military base’s prison later in the day, Army spokesman Wayne Hall said. He said the 28-year-old transgender soldier, who is appealing her 2013 conviction and 35-year prison sentence, was being monitored.

Hall and other Pentagon officials declined to say why the Army private was hospitalized. Fort Leavenworth spokeswoman Denise Haeussler said federal privacy laws precluded her from commenting without Manning’s consent.

CNN said that it was believed that the 28-year-old had tried to kill herself.

There was no immediate independent confirmation of this. A spokesman for the US Army told The Independent he was waiting for an approved statement before being able to comment. TheWashington Post reported that the military said Manning had since been returned to her cell but provided no other details.

Leaks to media outlets about the hospitalization angered Manning’s appellate attorneys, who said they weren’t apprised of the hospitalization. Manning’s sister, Casey Major, said she also was unaware of the matter until reached Wednesday by the AP.

Manning’s lawyer, Nancy Hollander, said in a statement that she was “shocked and outraged” that an official at Fort Leavenworth provided “confidential medical information” about Manning to the media but had not shared anything with her team. She said she had been due to speak with her client at 2pm on Monday but was told she could not be connected.

“Despite the fact that they have reached out to the media, and that any other prison will connect an emergency call, the army has told her lawyers that the earliest time that they will accommodate a call between her lawyers and Chelsea is Friday morning,” she said.

“We call on the army to immediately connect Chelsea Manning to her lawyers and friends who care deeply about her well-being and are profoundly distressed by the complete lack of official communication about Chelsea’s current situation.”

The base declined the AP’s request Wednesday for a telephone interview with Manning.

Manning, arrested as Bradley Manning, was convicted in military court of six Espionage Act violations and 14 other offenses for leaking more than 700,000 secret military and State Department documents, plus some battlefield video. Manning, who was an intelligence analyst in Iraq at the time, later filed a transgender prisoner rights lawsuit.

Manning has appealed the criminal case, arguing that her sentence was “grossly unfair” and that her actions were those of a naive, troubled soldier who aimed to reveal the toll of the wars in Iraq and Afghanistan. The appeal contends Manning’s disclosures harmed no one, but prosecutors have said the leaked material damaged U.S. security and identified informants who helped U.S. forces.