Foreign journalists working in China say reporting conditions, including police harassment, have worsened, while analysts point to a political power struggle for China's leadership succession next year.
According to a recent survey carried out by the Beijing-based Foreign Correspondents' Club of China (FCCC), the majority of foreign journalists believe that reporting conditions have got worse during the past year.
And 70 percent said that they had been subjected to police harassment in the course of their work.
The FCCC published the preliminary results of its survey on Thursday, revealing growing friction between journalists and police who have tried to deter reporting from sites of potential protest.
A crackdown in recent weeks sparked by online calls for a "Jasmine" revolution in the wake of recent uprisings in the Middle East led to a number of reports of beating and roughing up of foreign journalists by police.
The scuffles and attacks took place in locations designated by online groups as anti-government protest sites in recent weeks, amid growing tension between the foreign media and the ruling Communist Party.
Beijing has denied its police beat any foreign journalists, meanwhile warning them to do as they are told by the authorities when out on reporting assignments.
The FCCC annual survey drew 108 responses from 225 members, and 94 percent of those who answered said reporting conditions had deteriorated.
"Seventy percent of respondents said they had experienced interference, harassment and/or violence in the past year," Reuters quoted the FCCC as saying.
Chinese foreign ministry officials dismissed the survey, saying that press freedom in China is on the increase.
But Beijing-based foreign correspondents say they have been warned that they risk having their visas revoked if they try to report from designated protest sites without permission.
And foreign journalists in Beijing said they have received phone calls or home visits from the police to check their paperwork and remind them about the need to follow reporting rules.
Former chairman of the Hong Kong Journalists' Association Camoes Tam said the media crackdown is linked to the current political climate in mainland China.
"The current tightening of media controls is to do with the ...18th Party Congress next year, at which there will be some changes in political leadership," Tam said.
"Naturally, this is going to lead to some power struggles."
Clampdown on domestic media
He said the more restrictive attitude to the media isn't just aimed at foreign journalists in China, however.
"They are also clamping down very tightly on China's domestic media outlets," he said.
However, Tam said it is unlikely that the authorities will ever be able to completely restrict the flow of information over the Internet.
"People in mainland China are continually adopting the latest technology to get over the Great Firewall (GFW)," he said. "They are using every method to continue to avoid the Party's control."
Former Beijing University journalism professor Jiao Guobiao blamed a deep-rooted fear of the media among China's leadership elite.
"It's a psychology of fear," Jiao said. "Actually I think that most Chinese people no longer get their nonofficial news from overseas media."
"I don't really think it will have much effect, to place restrictions on foreign journalists."
He said that while controls on the media have intensified in recent years, so have the efforts of some Chinese journalists to break through them.
"This is a protest on behalf of their professional ethics and ideals," Jiao said.
Reported by He Ping for RFA's Mandarin service. Translated and written in English by Luisetta Mudie.