TAIPEI — Lee Ming-cheh, a human rights advocate from Taiwan who was detained in China in March, has been formally arrested on a charge of “subverting state power,’’ the Chinese government said, amid a continuing crackdown on civil society organizations.

His arrest, revealed Friday, marks the first time Chinese authorities have charged someone from Taiwan with subversion. Many people in Taiwan fear it will not be the last, and it has added a new strain to the tensions between Beijing and Taipei.

China’s ruling Communist Party has never administered Taiwan but claims it as Chinese territory, to be annexed by force if necessary.

The Nationalists who once dominated China fled to the island after losing to the Communists in a civil war in 1949.

Today more residents of Taiwan identify themselves as Taiwanese than Chinese, and few support unification with China.

The rift between the two sides has widened since last year, when Tsai Ing-wen was elected president of Taiwan.

The Democratic Progressive Party, led by Tsai, has historically favored formal independence from China.

Beijing broke off official communications with Taiwan after Tsai, in her inauguration speech, declined to yield to Chinese demands that she endorse a political formula that holds that Taiwan is part of “One China’’ that includes both mainland China and Taiwan.

Lee was detained March 19 after crossing into mainland China from Macau, a former Portuguese colony that has limited autonomy from Beijing. Since then he has been held incommunicado, denied family visits and access to lawyers.

In the announcement of Lee’s arrest, An Fengshan, a spokesman for China’s Taiwan Affairs Office, said Lee visited China frequently over the past five years and “colluded with relevant individuals in the mainland, laying down an operational program, establishing an illegal organization, and planning and implementing activities to subvert state power.’’

An offered no evidence to support these claims.

The Chinese government has in recent years increasingly used the crimes of “subversion’’ or “inciting subversion’’ to imprison political dissidents and human rights advocates.

Chinese courts come under Communist Party control and rarely reject the prosecution’s case, especially in politically charged trials.

Defendants found guilty of subversion can face up to life in prison, although shorter sentences are more common.

Last year, Peter Dahlin, a Swedish man living in Beijing who helped train Chinese legal advocates to challenge government decisions, was detained in secrecy and then expelled after he was made to confess on television.

An said that Lee and his Chinese associates had “candidly confessed’’ to the allegations. He did not give any details.