BEIJING >> China sentenced a Taiwanese activist to five years in prison Tuesday for holding online political lectures and helping the families of jailed dissidents in a conviction demonstrating how Beijing’s harshest crackdown on human rights in decades has extended beyond the Chinese mainland.

The trial of Lee Ming-che was also China’s first known criminal prosecution of a nonprofit worker since Beijing passed a law last year tightening controls over foreign non-governmental organizations.

The Yueyang City Intermediate People’s Court in central China handed down the sentence against Lee after finding him guilty of subversion of state power. Lee had confessed during his trial in September, which his wife dismissed as “a political show.”

Lee’s co-defendant, Peng Yuhua, who is from mainland China, was sentenced to seven years’ imprisonment. Peng had also pleaded guilty, saying he had founded an organization called Palm Flower Co. to pressure China to accept a multiparty political system and that Lee was his deputy in charge of education.

Lee’s wife Lee Ching-yu attended the sentencing. “A price must be paid in the pursuit of an ideal,” she said in a statement issued through her supporters. “Striving for human rights for the underprivileged is a necessary dedication to promoting the progress of human civilization.”

Supporters say that since the trial ended Lee Ching-yu has been prevented from leaving her hotel room or meeting with anyone. Calls to her mobile phone rang unanswered.

“Lee Ming-che took the risk despite knowing the dangers,” she said, adding that she was proud of him.

Subversion of state power is a vaguely defined charge often used by authorities to muzzle dissent and imprison critics. Both men said they would not appeal.

Taiwan, a self-governing island Beijing regards as part of Chinese territory, swiftly condemned the sentence.

“The spread of democratic ideas is innocent!” Alex Huang, the spokesman of Taiwanese President Tsai Ing-wen, said in a statement. Huang urged Beijing to release Lee as soon as possible and allow him to return to Taiwan.

“We cannot accept that Lee Ming-che has been convicted of ‘state subversion’ for sharing ideas of freedom and democracy out of concern for the development of mainland China’s civil society and democracy,” the statement said.

Taiwan’s Cabinet-level Mainland Affairs Council said in a statement it would not accept the verdict against Lee and said the government would continue working to secure his release from China.

Lee Ming-che, 42, cleared immigration in the semi-autonomous Chinese territory of Macau on March 19 and never showed up for a planned meeting later that day with a friend in the mainland Chinese city of Zhuhai.

He had previously conducted online lectures on Taiwan’s democratization and managed a fund for families of political prisoners in China.

China’s wide-ranging crackdown on civil society has featured a string of televised “confessions” — believed to have been coerced — from human rights activists accused of plotting to overthrow the political system.

The new law passed in April 2016 says foreign NGOs must not endanger China’s national security and ethnic unity, and places nonprofit groups under close police supervision. It is seen as an attempt to clamp down on perceived threats to the ruling Communist Party’s control.

Relations between Taiwan and China have been near an all-time low since the election of Tsai, whose party has advocated Taiwan’s formal independence. China cut off contacts with Taiwan’s government in June of last year, five months after Tsai was elected.

Amnesty International said Lee Ming-che was a victim of a politically motivated prosecution and that the evidence against him was not credible.

“He is the latest to suffer under the Chinese authorities’ relentless attack against human rights and democracy activists,” Roseann Rife, the group’s East Asia research director, said in a statement.