BEIJING • A prominent human rights activist in China has been found guilty of subverting state power after a one-day trial in the northern city of Tianjin.

Zhai Yanmin, 55, was among 300 lawyers and activists arrested since July last year as part of the so-called "709 crackdown" on legal activism.

In the first trial since the crackdown, which was launched on July 9 last year, Zhai was sentenced yesterday to a three-year jail term, suspended for four years.

He was convicted of "subverting state power" for acts including waving banners and shouting slogans in four protests since 2014, Xinhua news agency cited the court as saying.

The sentence, relatively lenient by the standards of Chinese dissident prosecutions, came after Zhai "admitted" to prosecutors' accusations in court, Xinhua said.

Zhai repeatedly posted views online subverting the government and had worked with lawyers, including Zhou Shifeng and Li Heping to hype cases and "systematically undermine state power", Xinhua cited prosecutors as saying.

Those actions "seriously harmed state security and social stability", it said.

Zhou and Li, who face the same charge as Zhai, are expected to go on trial this week.

Another well-known human rights lawyer, Mr Li Fangping, told Reuters that the reprieve accompanying the sentence means that Zhai should be released, although he is likely to be strictly monitored.

China's President Xi Jinping has overseen a tightening of controls on civil society since assuming power in 2012, closing avenues for legal activism which emerged in recent years.

Evidence presented at yesterday's trial, which apparently lasted only three hours, included banners, books and "audio and video recordings", Xinhua said, without giving their provenance.

In his final statement, Zhai told the court he pleaded guilty and wanted to remind the public to be aware of the "true meaning behind the slogans about democracy and human rights".

He also pledged in the court that he would not talk to any foreign media or media "hostile" to Beijing, according to South China Morning Post.

No family member attended the hearing, but Zhai claimed that was his choice.

"I made a call to tell my family not to come, in case they couldn't accept the verdict," he told reporters of several media outlets who were allowed into the courtroom.

Zhai's activism began with the Tiananmen Square protests in 1989, according to BBC News.

In addition to a few mainland media, the Ministry of Public Security invited four Hong Kong-based media outlets and one from Taiwan to attend the hearing.

On Monday, another human rights lawyer, Wang Yu, delivered a scathing rebuke of her profession in a televised confession on Monday. Also detained during the crackdown, she was released in July on bail pending trial.

In the video, she accused colleagues of pursuing wealth and fame and suggested that foreign activists were conspiring to smear the Chinese government, reported New York Times.

"I won't be used by them anymore," she said in a video posted by The Paper, a Communist Party-controlled news site.

In the video, she denounced Mr Zhou Shifeng, the head of Beijing Fengrui law firm, as an unqualified lawyer, reported BBC News. The law firm had worked extensively on human rights cases until it was shut down in July 2015.