Police in China have arrested one of the country's most celebrated human rights lawyers as leaders of the ruling Communist party renew their push to punish government critics.

Pu Zhiqiang, a prominent campaigner who has represented the dissident artist Ai Weiwei, was arrested on suspicion of "creating disturbances and illegally obtaining personal information", said the Beijing Public Security Bureau.

A further investigation into Pu's "other alleged crimes" was under way, the police said.

Pu's lawyer, Si Weijiang, said political reasons were behind the arrest. "He's innocent. He hasn't committed these crimes," Si told Agence France-Presse by phone on Friday night.

He said authorities had likely been incensed by critical statements Pu had made on his microblogging account, which has repeatedly been shut down.

Pu was among several people detained last month after attending a private seminar commemorating the 25th anniversary of the Tiananmen Square crackdown.

More than 40 journalists, lawyers, scholars and activists were held under various forms of detention ahead of the 4 June anniversary, Amnesty International said, in a larger clampdown than in previous years.

Concerns about Pu's condition began to mount days after the anniversary when he remained in detention even as other activists and lawyers were released.

Courts in China are controlled by the government and arrests typically lead to conviction.

Zhang Sizhi, a longtime rights lawyer, wrote in an online posting on Wednesday that he was able to meet with Pu this week and the detained lawyer had been subjected to daily interrogations lasting as long as 10 hours.

Several associates of Pu were detained ahead of the Tiananmen anniversary including the journalist Wu Wei and Xin Jian, a Chinese staff member of the Japanese financial newspaper Nikkei who recently interviewed the lawyer. Wu and Xin were released last week, according to campaign groups.

As news of Pu's arrest circulated late on Friday, Ai – the dissident artist who repeatedly clashed with authorities and has been denied a passport – made note of the arrest on his Instagram photo-sharing account.

He posted a photo of Pu, a news story about the arrest and a Chinese-language expletive in the comments section below.