A Swedish bookseller and author who sold sensitive titles about China's leaders was sentenced by a Chinese court to 10 years in prison for "illegally providing intelligence" to overseas parties, in a case that highlighted the Communist Party's intolerance of criticism and strained relations between Beijing and the West.

The judgment against Gui Minhai was handed down Monday by the Ningbo Intermediate People’s Court but was not made public until Tuesday.

Human rights advocates decried the ruling as politically motivated and another heavy-handed attempt by Communist leaders to silence their detractors. Gui also appears to have been forced to renounce his Swedish citizenship.

In addition to the prison term, the court indicated Gui would be deprived of the right to freedom of assembly or association and banned from holding positions in state organs or companies for an additional five years.

It said Gui agreed with the sentence and would not file an appeal. The court added that the bookseller, who became a Swedish citizen in 1996, “regained his Chinese citizenship on his own, according to the rule of law, in 2018.” China does not recognize dual nationality.

In Stockholm, Foreign Minister Ann Linde said the Swedish government still insists that Gui be released.

“We are now seeking more information,” she wrote on Twitter, adding that Swedish diplomats did not have access to the trial. “The government continues to demand that Gui Minhai be released and that we have access to our citizens to provide consular support.”

In Beijing, Chinese Foreign Ministry spokesman Zhao Lijian said that Gui’s “rights and interests have been fully guaranteed.” He said Swedish diplomats have not had consular access to Gui “due to coronavirus containment efforts.”

Gui, 55, was part-owner of Hong Kong’s Causeway Bay Books, known for selling politically sensitive publications and gossip about top Communist Party leaders, including General Secretary Xi Jinping.

He was kidnapped in Thailand in 2015, around the same time that several other people affiliated with the bookstore also vanished — an operation widely believed to be the work of Chinese agents. Gui reappeared in Chinese custody months later and delivered a scripted confession in which he suggested he had secretly smuggled himself to China to turn himself in for his involvement in a 2003 car crash. He also said he didn’t want help from Swedish authorities.

Authorities partially released him in October 2017 and allowed him to travel within China. But in 2018, Gui was detained, snatched by Chinese plainclothes police officers as he rode a train from Shanghai to Beijing while accompanied by Swedish diplomats.

In a video released after that second detention, Gui, flanked by two police officers, said he was “ashamed” and had “made mistakes,” adding that Sweden had used him like a “chess piece.”

Friends and activists said the video was staged and that Gui spoke those words under duress.

Little had been heard of him since, and relations between Sweden and China deteriorated. This was complicated by a bizarre incident in which Sweden’s ambassador to China, Anna Lindstedt, arranged a meeting in Stockholm between Gui’s daughter, Angela Gui, and Chinese representatives.

The meeting came to light when Angela Gui wrote a Medium post about it. The Swedish Foreign Ministry said it had no knowledge of the meeting, and Lindstedt was recalled from her post. She faces criminal charges.

China’s ambassador to Sweden, meanwhile, has emerged as one of the country’s most aggressive diplomats, giving interviews including one in which he appeared to threaten local journalists who write critically about Beijing.

The ambassador, Gui Congyou — no relation to the bookseller — last month slammed Swedish reporting on the Chinese government, accusing the journalists of “criticizing, accusing and smearing China,” and he implied retaliation. He compared the relationship between Swedish reporters and the Chinese government to a 100-pound boxer challenging a 190-pound boxer to a fight.

Human rights advocates sharply criticized the court ruling against the bookseller.

“Today’s sentence of Gui Minhai is an indictment not of him but of the Chinese government’s bottomless hostility towards critics and shameless misuse of its legal system,” said Sophie Richardson, China director at Human Rights Watch. “Gui has committed no crime and should be released immediately.”

Patrick Poon, China researcher at Amnesty International, said the decision was “deplorable” and lacking in transparency.

“Gui has been detained since he went missing in Thailand in 2015. It’s just bizarre to accuse him of providing intelligence while he’s under custody,” he said.