Journalists at one of China's main liberal newspapers are calling for the resignation of a Guangdong province censor to resign after he changed an editorial in the publication.

Thirty-five editorial staff members, including former journalists and 50 intern reporters, at the Southern Weekly are up in arms over censor Tuo Zhen altering a New Year's editorial calling for guaranteed constitutional rights to one praising the Communist Party, a report by the BBC said.

Journalists at the Southern Weekly -- noted for its investigative journalism -- said the changes were "crude" interference by Tuo who was acting in a "dictatorial" fashion in an era of "growing openness," the BBC report said.

"If the media should lose credibility and influence, then how can the ruling party make its voice heard or convince its people?" the journalists' said in an open letter.

The BBC's Chinese section editor Zhuang Chen said the call for Tuo's resignation is thought to be the first direct showdown between newspaper staff and party officials.

The government has reacted to the call by allegedly curbing Internet search facilities for Southern Weekly, in particular on the micro-blogging site Sina Weibo.

Search terms involving the Southern Weekly controversy are reportedly being filtered and users suspended from the service, the BBC said.

Another publication, online magazine Yanhuang Chunqiu -- China Through the Ages -- has called on China's leaders to guarantee constitutional rights such as freedom of speech and assembly.

The row is the latest clash between China's increasingly restive media and efforts by the central Communist Party in Beijing to control dissent as well as the county's burgeoning Internet pornography.

Last week the state news agency Xinhua reported that 45 million illegal publications had been confiscated in 2012.

The National Office Against Pornographic and Illegal Publications also reported nearly 4 million pieces of online information involving pornography and other illegal content had been deleted.

The government continues to prosecute violations and one ringleader in Beijing was sentenced to 14 years in prison for selling over 35,000 pornographic products.

A court in Hotan City, Xinjiang Uygur Autonomous Region, sentenced a man to 10 years in prison for selling illegal publications, the Xinhua report said. Two men received prison sentences or around 40 months for printing and selling pirated textbooks.

Chinese officials said they also would clamp down on "unlicensed reporters" to "preserve the reputation of the country's news media," Xinhua said.

Liu Binjie, head of the General Administration of Press and Publication, said the government would be on the lookout for publications issuing press cards to unqualified reporters.

China's relationship with foreign journalists also was under scrutiny when officials didn't renew the visa of New York Times correspondent Chris Buckley.

Buckley, who had worked in China since 2000 for The New York Times and for Reuters, left Beijing for Hong Kong after his visa expired.

Buckley was among the foreign reporters breaking news last year on the scandal involving Bo Xilai, the ambitious Communist Party politician purged in March.

"I regret that Chris Buckley has been forced to relocate himself outside of China despite our repeated requests to renew his journalist visa," said New York Times Executive Editor Jill Abramson in a statement, noting Philip Pan, the Times' Beijing bureau chief, also awaits his visa.

But the government said Buckley never was asked to leave and that his problem was one of protocol and who is his official employer.

"The New York Times claimed Chris Buckley as its Beijing correspondent, but as we all know, he has been holding credentials for another foreign media outlet for years," Ministry of Foreign Affairs spokeswoman Hua Chunying said, referring to the news agency Reuters.

Hua said if Buckley had resigned from Reuters, the agency should have completed the reporter's resignation procedures with the Ministry of Foreign Affairs, in accordance with Chinese regulations.

"So far, we have neither received any notice of resignation (from Reuters), nor has the press card issued by the information department of the foreign ministry been returned by Chris Buckley," Hua said.

"So we do not know who his real boss is now."