A court in eastern China has sentenced a Swedish seller of books that took a skeptical look at the ruling Communist Party to 10 years in prison for "illegally providing intelligence overseas," in a further sign of Beijing's hard line toward its critics.

Gui Minhai first disappeared in 2015, when he was believed to have been abducted by Chinese agents from his seaside home in Thailand. He and four others who worked for the same Hong Kong publishing company all went missing around the same time, only to turn up months later in police custody in mainland China.

The Ningbo Intermediate People's Court announced Tuesday that it gave Gui, a naturalized Swedish citizen, a 10-year prison sentence. Gui admitted to his crime, agreed with the sentence and will not appeal, the court said.

For years, Gui sold gossipy books about Chinese leaders in the semi-autonomous Chinese region of Hong Kong. His was among a spate of high-profile disappearances that stirred unease over the central government's growing reach in Hong Kong, a former British colony that has been promised greater democratic rights than are afforded the mainland.

China maintains tight control over all information and brooks no criticism of its ruling Communist Party. It has detained scores of lawyers, writers and public intellectuals. In recent months, police have reprimanded medical workers who warned about the ongoing outbreak of a new virus that originated in the Chinese city of Wuhan.

Amnesty International's China researcher Patrick Poon said the verdict demonstrated that "the Chinese authorities are not letting the coronavirus crisis distract them from repressing dissidents."

"Despite the authorities' claim that Gui has somehow handed over `intelligence' while in their custody, the reason for his targeting almost certainly relates to his attempted trip to Beijing with two Swedish diplomats in 2018," Poon said in an emailed statement.

Sweden demands access

The court claims that Gui, who was born in Ningbo, applied to reinstate his Chinese citizenship in 2018. That would mean renouncing his Swedish citizenship, as China does not officially allow dual citizenship.

He was initially released into house arrest in Ningbo, then police detained him once again while he and two Swedish diplomats were on a train together bound for Beijing.

"We have noted the reports and are now seeking official confirmation about the case," the Swedish foreign ministry said in an email to The Associated Press. "We have consistently made it clear that we demand Gui Minhai be released so that he can be reunited with his daughter and family."

The foreign ministry said that Sweden was not given access to the trial, and that officials there were unable to review the indictment or offer Gui access to legal counsel.

"We demand — once again — that we immediately be given consular access," the ministry said.

Gui's arrest has been a source of friction between Beijing and Stockholm. In November, Sweden's culture minister awarded the bookseller the annual Tucholsky literary prize despite a threat from the Chinese ambassador to ban her from entering the country.

Standing next to Gui's empty seat at a ceremony in Stockholm, Culture Minister Amanda Lind said it was "crucial for culture and democracy that artists and authors can work freely."

Human rights groups have repeatedly accused China of extracting forced confessions from individuals it perceives to be opponents of the Communist Party's rule.

"We demand Gui Minhai's release," Swedish Foreign Minister Ann Linde told Sweden's public broadcaster SVT.

She stressed that Sweden was not informed about the trial and that the country will use "all diplomatic tools" to protest.

"We got no information that this was going on and had not had access to either the trial or been allowed to see the charges," Linde told SVT. "This is not at all in line with how diplomatic consular work is going. We have the right to gain access to Swedish citizens. We have demanded it, but didn't get it."

Repeating an assertion often made by Beijing when its judicial system faces scrutiny, Chinese Foreign Ministry spokesman Zhao Lijian said at a daily briefing, "China is a country ruled by law."

"Gui Minhai's legal rights and interests have been fully protected," Zhao said, adding that China opposes outside interference into its internal affairs.