The United States warned China on Friday against any move to declare a new air defense zone over parts of the South China Sea including disputed islands.

The Asahi Shimbun daily of Japan reported that Chinese air force officials have drafted proposals for the next Air Defense Identification Zone (ADIZ) that could place the Paracel Islands at its core.

Any such move would be seen "as a provocative and unilateral act that would raise tensions and call into serious question China's commitment to diplomatically managing territorial disputes," State Department deputy spokeswoman Marie Harf told reporters.

She stressed, however, that the reports were "unconfirmed" at this time.

Beijing claims the South China Sea almost in its entirety, even areas a long way from its shoreline.

Late last year, it caused a storm when it abruptly declared an ADIZ above the East China Sea, including islands at the heart of a sovereignty row with Tokyo.

"We've made very clear that parties must refrain from announcing an ADIZ or any other administrative regulation restraining activity of others in disputed territories, and we would of course urge China not to do so," Harf added.

China hits back at US criticism over foreign journalists
Beijing (AFP) Jan 31, 2014 - China on Friday hit back at Washington's condemnation of its treatment of foreign journalists, as tensions rise over a New York Times reporter who left Beijing after not receiving a visa.

The case of reporter Austin Ramzy, who departed Beijing for Taipei on Thursday, has sparked protests from the White House and elsewhere that China is seeking to retaliate against news organisations such as the Times and financial news agency Bloomberg that have published investigations into the family wealth and connections of its top leaders.

"China does not accept the unjustifiable accusations by the US side, and demands the US side to respect facts and take cautious words and acts," Chinese foreign ministry spokesman Hong Lei said in a statement reported Friday by the official Xinhua news agency.

Hong added Washington must behave in a way that was more "conducive to media exchanges and mutual trust between the two countries".

Hong's sharp retort came after the White House said it was "deeply concerned that foreign journalists in China continue to face restrictions" following Ramzy's departure for Taipei, where he will report while continuing to seek a visa for mainland China.

Ramzy, who had been based in China for more than six years, left Time magazine in mid-2013 to work for the New York Times.

'Forced out'

But Chinese officials had not yet granted him a new visa before his previous one expired, effectively obliging him to leave Beijing.

"China is forcing out Austin Ramzy today after 6.5 years," Times China correspondent Ed Wong wrote Thursday on Twitter.

Ramzy confirmed his arrival in Taipei via Twitter Thursday night. In an earlier message, he wrote: "Sad to be leaving Beijing. Hope I can return soon."

Ramzy's departure comes a month after US Vice President Joe Biden raised the issue of China's treatment of foreign journalists privately with Chinese leaders during a visit to Beijing.

Beijing has blocked the websites of both the Times and Bloomberg after they published investigations in 2012 into the family wealth of former premier Wen Jiabao and President Xi Jinping, respectively.

Authorities also reportedly conducted unannounced "inspections" of Bloomberg's offices in Beijing and Shanghai last month and demanded an apology from its editor-in-chief amid a controversy over an unpublished article on the government ties of a Chinese billionaire.

The Foreign Correspondents' Club of China (FCCC) said it "strongly regrets" that Ramzy "has been forced to leave" and criticised China's behaviour, saying it "falls well short of international standards".

He is the third New York Times journalist not to be authorised to stay in China in 18 months, it pointed out in a statement.

"In these circumstances it is difficult to avoid the conclusion that the authorities are punishing the New York Times for articles it published concerning Premier Wen Jiabao and his family."

Chris Buckley, a veteran Reuters China correspondent hired by the Times, similarly had to leave Beijing when his previous visa expired in December 2012.

Philip Pan, the Times's designated Beijing bureau chief, has been waiting for nearly two years for Chinese authorities to grant him a visa and covers the country from Hong Kong.

'No such thing as expulsions'

Asked about China's treatment of foreign journalists, foreign ministry spokeswoman Hua Chunying denied any expulsions.

"There's no such thing as foreign journalists being expelled from China," Hua said Wednesday at a regular news briefing, adding: "It is Chinese domestic affairs.

Chinese authorities have said that Ramzy breached visa rules by not changing his status after leaving Time, but the FCCC disputed the accusation.

On Thursday, the White House said the US was "very disappointed" that Ramzy was obliged to leave China and that Beijing's actions "stand in stark contrast with US treatment of Chinese and other foreign journalists".

"The United States is deeply concerned that foreign journalists in China continue to face restrictions that impede their ability to do their jobs, including extended delays in processing journalist visas, restrictions on travel to certain locations deemed 'sensitive' by Chinese authorities and, in some cases, violence at the hands of local authorities," it said in a statement.

Last week, foreign journalists covering the trial of activist Xu Zhiyong in Beijing were harassed and manhandled by uniformed and plainclothes police.