A 71-year-old Chinese journalist imprisoned on a state secrets conviction was released for medical reasons Thursday after pleading guilty during a closed-door appeal hearing, her lawyers and state media said.

Gao Yu, one of the best-known intellectuals to have been imprisoned for supporting the 1989 Tiananmen pro-democracy protests, was detained again last year on charges of leaking a document to the media detailing the Communist Party leadership's resolve to tamp down on Western notions of constitutionality and freedom.

She refused to admit guilt during her April trial, when she was sentenced to seven years in prison, and later appealed the conviction.

When Beijing's high court heard her case Tuesday, Gao pleaded guilty, which is normally seen by courts in China as contrition deserving of leniency. However, her defense continued to argue for her innocence, her lawyers said.

The court reduced her sentence from seven years to five years. Later Thursday, the official Xinhua News Agency announced that the court had decided that Gao is qualified to serve her sentence outside of prison because of "severe illnesses."

"We had expected her to be released for medical reasons, but it came as a surprise" that the release came so soon, lawyer Shang Baojun said, adding that Gao has heart problems.

Gao was convicted of leaking the official report — known as Document No. 9 — to an overseas news site. The site, Mingjing News, has said Gao did not provide the document, and her lawyers said they presented evidence to the appeal court that Gao was not the source of the report.

Foreign governments and human rights groups have denounced the verdict against Gao as politically driven retribution for her criticism of the government, and urged authorities to release the elderly journalist.

Before her April trial, Gao appeared on state television and said she was guilty, but she told the trial court that police had threatened her son to force her into making the confession.

Gao was also imprisoned on state secrets charges for more than a year after the 1989 crackdown. She was detained again in April last year, weeks before the 25th anniversary of the bloody military suppression of the protests that killed at least hundreds of people.