Chinese police have arrested prominent writer Ran Yunfei for challenging the ruling Communist Party, people close to the blogger said on Monday, the latest in a string of arrests in a deepening crackdown on dissent.

Ran, a writer and literature magazine editor from southwest Sichuan province, who had been detained without charge for more than a month, was formally arrested on the charge of inciting subversion of state power, Wang Yi, a Christian activist in Sichuan and a friend of Ran, told Reuters.

Ran, 46, was detained by police in Chengdu on February 20 as unrest rippling across the Middle East generated online calls for similar Jasmine Revolution protests in China.

The charge of inciting subversion was also used to jail Liu Xiaobo, the dissident who won the Nobel Peace Prize, which infuriated Beijing.

Basically, it's the crime of expressing your opinions, said Wang, formerly a legal scholar. In this case, too, the prosecutors will probably use essays that Ran has published on the Internet.

Nobel Laureate Liu has been serving an 11-year sentence since 2009 for co-writing the Charter 08 manifesto that called for sweeping political reform and is seen as one of the boldest challenges to Communist Party rule in recent memory.

The Chinese authorities are seeking to stifle any potential challenge to their power ahead of a Party leadership handover in late 2012.

Wang said Ran's wife received the arrest notice on Monday, although it was dated last Friday, the day a court sentenced another leading dissident in Sichuan, Liu Xianbin, to 10 years in prison for urging democratic reform.

Rights campaigners said that long sentence could augur tough punishment for other detained activists.

Liu Xianbin is not related to Liu Xiaobo.

The arrest was confirmed by another person close to Ran, who asked not to be named out of fear of retribution for speaking to foreign reporters.

Police also searched Ran's home in February and confiscated his computer, according to Reporters Without Borders. Ran's formal arrest could culminate in a trial and a maximum prison sentence of five years.

The authorities have detained dozens of lawyers, bloggers and dissidents in what rights groups say is China's harshest crackdown on dissent in recent years.

More than 100 activists, many of them active on Twitter and blogging sites, have been detained, subjected to monitoring and intimidation by the security forces or have gone missing since late February, particularly after the online calls for Jasmine gatherings, according to Amnesty International.

Prosecutors could order further investigations of Ran and it could be up to four months or more before Ran's fate becomes clear, Wang said. He and others familiar with Ran said they did not know specifically what triggered the arrest.

Ran was a signatory of Charter 08.

The government on the one hand prevents freedom of the press and disallows the free flow of information, and on the other hand ... conceals the truth, Ran wrote on his Twitter account on Feb 14. It's no wonder that rumors are prevalent under these circumstances.

(Reporting by Sui-Lee Wee and Chris Buckley; Editing by Ken Wills and Alan Raybould)