A recent report speculating on whether China will designate an air defense identification zone in the South China Sea is covering old ground, sources told China Daily.

The intention may be to hold China accountable for the rising tension there, said the sources, who spoke on condition of anonymity.

After China established an ADIZ for the East China Sea in November 2013, speculation on another such zone for the South China Sea made global headlines. To protect a country's sovereignty and territorial and airspace security, aircraft entering such a zone would be required to identify themselves.

The latest speculation was reported on Wednesday by the South China Morning Post, which quoted an unnamed source as saying that "if the US military keeps making provocative moves to challenge China's sovereignty in the region, it will give Beijing a good opportunity".

Speaking on condition of anonymity, the sources close to the matter told China Daily that the Ministry of National Defense had responded to such speculation before.

"There have been voices hyping the ADIZ in the South China Sea or sensationalizing what they claim as China's massive construction work there. ... They all have one common target: to hold China accountable for the rising tension in the South China Sea," one of the sources said.

As to the timing of such claims, another source said a possible intention is to "further attract critics and attention, shape China's image as 'assertive' in the South China Sea, and prevent the tension there from cooling down".

Another possible intention, the source added, is that "China has legally tackled, in a reasoned and justified approach", the US "freedom of navigation program", which saw US military vessels recently infringe on China's territorial sovereignty.

"The relevant parties or individuals know clearly that they are in the wrong, and they are keen to shift focus and attention, so they seek to once again hype the ADIZ topic and accuse China of militarizing the South China Sea," the source said.

Zhou Fangyin, a professor at the Guangdong Institute for International Strategies, said the recent news reports show an intention to make China the "bad guy". Some people want to "remind constantly" that China is the one allegedly stirring up trouble, while in fact it's the US that has been provoking in the region, said Zhou.

Wang Qingyun contributed to this story.