Chinese police have detained a human rights lawyer who called for the release of activists arrested for demanding that government officials disclose their assets, a lawyer said Wednesday.
Xu Zhiyong, a lecturer at a Beijing university, was held by police on Tuesday for "disturbing order in a public place", his friend and fellow lawyer Teng Biao wrote on a Twitter account.
Rights groups called Xu's arrest the latest episode in a crackdown on political activists launched after President Xi Jinping was formally appointed in March.
At least 24 activists have been detained since late March, US-based advocacy group Chinese Human Rights Defenders said in a statement.
Chinese citizens are regularly scandalised by reports of corrupt officials living lavish lifestyles, leading to calls for laws requiring government officials to publicly list their assets.
Bloomberg news agency last year reported that Xi's family had assets worth $376 million, while the New York Times reported that relatives of former Premier Wen Jiabao had controlled assets worth $2.7 billion.
A co-ordinated crackdown was "targeting a loose grouping of activists... who have peacefully advocated for democratic and rule-of-law reforms, constitutionalism, human rights and social justice", Chinese Human Rights Defenders said.
Three anti-corruption activists detained in April in the central province of Jiangxi are awaiting trial on charges of illegal assembly, which carry a maximum sentence of five years in prison, lawyer Zheng Jianwei told AFP.
Xu signed an open letter in April calling for them and other activists seeking assets disclosure to be released, US-based advocacy group Human Rights in China said in a statement.
Xu, a prominent lawyer and advocate of legal reform, was arrested in 2009 on tax evasion charges, which were dropped following condemnation by rights groups.
Teng Biao could not be reached for comment on Wednesday, after writing on Twitter that his phone had been disabled.
President Xi has vowed to crack down on all forms of corruption, saying it threatens the future of the ruling Communist Party.