China took offence on the regular air quality advisories issued by the U.S. diplomatic mission in the country, which Beijing claimed was not only inaccurate but also contradict the official notices issued by the country's environment officials.

Main point of contention is the Twitter feeds being maintained by the U.S. Embassy in Beijing with corresponding editions in two of China's biggest metropolis - Guangzhou and Shanghai.

According to China's Environmental Minister spokesman Wu Xiaoqing, U.S. Embassy officials should halt its practice of feeding hourly updates on the quality of air in key Chinese cities.

In a news briefing held on Tuesday in Beijing, Mr Wu stressed that the reports represent an unfair assessment of air quality in the country since they employ gauges that were solely determined by the United States.

Air quality measurements that were conducted within the Chinese borders, he added, must adhere to the Chinese standard, which "takes into account the level of our current stage of development."

The ministry official noted too that the U.S. economy is already developed while that of China is still developing although the country has achieved last year the status of being the world's second biggest economy.

Mr Wu also asserted that only the Chinese government has the official function to monitor the country's air quality and issue reports on its findings.

He warned that such activities conducted by the U.S. Embassy and other diplomatic posts stationed in the country constitute a direct violation of the Vienna Convention on Diplomatic Relations.

The air quality reports also run in counter with China's existing laws and regulations, the local environment official said.

In a statement, however, the U.S. Embassy clarified that the Twitter feeds were meant to guide American nationals currently based in Chinese cities and not to be taken as the United States' official take on the air quality in China.

"The monitor is an unofficial resource for the health of the consulate community," The Associated Press (AP) reported the statement as saying.

In a separate briefing, China's Foreign Ministry has maintained that "this type of information should not be released to the public."

"Of course, if the foreign embassies want to collect air quality information for their own staff or diplomats, I think that is their own matter," an official of the ministry allowed.