BEIJING • A Chinese court sentenced Taiwanese democracy activist Lee Ming-cheh to five years in prison on Tuesday on charges of attempting to subvert state power, further souring cross-strait ties.

Lee sat nervously as the three-judge panel read the sentence at the Yueyang intermediate people's court in Hunan province, according to a video posted on the tribunal's social media account.

Taiwan and human rights groups immediately denounced the ruling as "unacceptable" and "politically motivated".

Lee - a non-government organisation worker who was arrested during a trip to the Chinese mainland in March - is the first Taiwanese person to be convicted in China on the political charge, according to Taiwan's Judicial Reform Foundation.

A Chinese co-defendant named Peng Yuhua was sentenced to seven years in prison.

The court said both men stated that they would not appeal against their sentences.

President Xi Jinping, who consolidated power at a Communist Party congress last month, has cracked down on dissent and tightened control on civil society since taking office in 2012.

Lee had confessed to the charges during his trial in September, stating that he had written and distributed online articles that criticised China's ruling Communist Party and promoted democracy among other topics.

His wife, Ms Lee Ching-yu, who attended the sentencing, said her husband had "paid the price" for his ideals.

"Fighting for human rights for the disadvantaged is a commitment that must be made to push for the enhancement of human civilisation... I want to express again that I am proud of his dedication," she said in a statement.

Taiwan's presidential office and the ruling Democratic Progressive Party called the verdict "unacceptable".

"We urged the Beijing authorities to release Lee and allow him to return to Taiwan soon. We regret that Lee's case seriously damaged cross-strait relations," the presidential office said in a statement. China sees self-ruled Taiwan as part of its territory waiting to be reunified.

Lee has long supported civil society organisations and activists in China, according to Amnesty International, and was said to have frequently travelled between the mainland and Taiwan.

He had shared "Taiwan's democratic experiences" with his Chinese friends online for many years and often mailed books to them, said the Taiwan Association for Human Rights.

AGENCE FRANCE-PRESSE