In the new case, Zhang Zhan was detained in August 2024 on allegations of "picking quarrels and provoking trouble" -- a charge routinely used by authorities to suppress dissent.

Reporters Without Borders (RSF) said the 42-year-old was arrested "following her reporting on human rights abuses by the Chinese regime".

Zhang was sentenced to four years in jail on Friday, according to RSF and a post on X by UK-based activist Jane Wang citing "reliable sources".

In the previous case, Zhang was detained in May 2020 after travelling to the central city of Wuhan, where she recorded smartphone videos that reported on the chaos at the pandemic's epicentre and questioned officials' handling of the situation.

She served four years behind bars in the 2020 case.

Zhang's latest trial reportedly took place on Friday at a court in Shanghai, RSF and other groups said previously.

But outside the court, officials declined to confirm the trial was happening.

A group of seven diplomats from European and North American countries who had requested to observe Zhang's case were turned away, on the grounds that their paperwork was not in order, AFP saw.

A spokesman for China's foreign ministry said he was not aware of the situation when asked about the case at a regular news conference on Friday.

The foreign ministry did not immediately respond to an AFP question Sunday asking to confirm the sentencing.

"Zhang Zhan sacrificed everything to expose abuses and human rights violations by the Chinese regime," said Aleksandra Bielakowska, RSF Asia-Pacific advocacy manager, in a statement on the sentencing.

Zhang's detention in August 2024 was for spreading "false information that seriously damaged the national image" on foreign social media, according to documents shared on X by Jane Wang, the UK-based activist.

In January, rights groups said Zhang had gone on hunger strike and was being force-fed through a gastric tube.