Declaring an air defense identification zone (ADIZ) is the right of a sovereign country and other countries should not "point their fingers" on this, China's defense ministry said Thursday in response to reports that the US would not recognize an exclusive zone in the South China Sea.

"Whether and when to do it depends on whether and to what extent China faces air security threat," Chinese national defense ministry spokesperson Yang Yujun told a press conference in Beijing on Thursday.

US Deputy Secretary of Defense Robert Work said Wednesday that the US has informed China it will not recognize an ADIZ in the South China Sea and would regard such a move as "destabilizing," Reuters reported.

China set up an ADIZ in the East China Sea in 2013 to "safeguard its sovereignty and airspace security."

The US and some countries have been expressing their worries about China establishing another ADIZ in the south.

China has not announced a clear plan on the South China Sea ADIZ.

Analysts said the US official's remarks were used to set an agenda for the meeting between Chinese President Xi Jinping and his US counterpart Barack Obama on Thursday and influence international opinion ahead of an international court ruling on a South China Sea arbitration filed by the Philippines.

The US side wanted to step up pressure on China by making assumptions as "there now seems to be no indication that China will set up an ADIZ," Liu Feng, a Hainan-based expert on the South China Sea, told the Global Times on Thursday.

Such moves to hype up tensions over the South China Sea were made to "justify the US military presence in the region as well as to secure its military expenditure budget in Congress," Liu noted.

"For China, the real one who is militarizing the South China Sea is the US, which conducts frequent naval operations such as patrols and intelligence gathering under the guise of freedom of navigation," Chen Xiangmiao, a research fellow at the National Institute for the South China Sea, told the Global Times.

When asked for comments on the recent deal allowing the US to use five military bases in the Philippines, Yang also said on Thursday that the US has strengthened its military presence in the Philippines and is pushing forward the militarization of the South China Sea.

The New York Times also reported Thursday on a recent encounter between a US Aegis cruiser and Chinese warships in the South China Sea.

However, not much hostility was felt in what The New York Times called the "exchange of weather pleasantries" in the encounters between the Chinese and US warships, which shows that there has been some tacit understanding that a military conflict will be avoided, analyst said.

The two countries established mutual trust mechanisms to report major military operations to each other and set a code of safe conduct during naval and air force encounters during Obama's state visit to China in 2014. Annexes on "notification of military crisis" and "encounters in the air" were later signed in September 2015, Xinhua reported.

The two sides are still trying to learn each other's bottom lines, Chen said.

In February, China's Ministry of National Defense confirmed that it would send naval ships to join the Rim of the Pacific 2016 multilateral joint maritime exercise from June to August in Hawaii.

"A lack of dialogue will be the greatest problem in the China-US relations," Chen said, noting that the South China Sea will see an increase in US naval and airforce operations in the future.