SHANGHAI — China has defended the reported deployment of missiles on an island it occupies in disputed waters in the South China Sea, saying such moves were legitimate defense, while state media said they did not amount to "militarization," as the U.S. government has claimed.

However, in a further sign of tension over the issue, Chinese media said if the U.S. carried on with what Washington says are “freedom of navigation” naval missions in the area — which Beijing says are intrusions into its territorial waters — “more military equipment should be deployed to counter U.S. provocations.”

China has not formally confirmed the deployment of HQ 9 anti-aircraft missiles on Woody Island — known as Yongxing Island by China — in the Paracels or Xisha island chain, as reported Tuesday by Fox News and later confirmed by officials in the U.S. and Taiwan (which, along with Vietnam, also claims sovereignty over the island). But China’s defense ministry said late Wednesday that it was “lawful for China to deploy defense facilities within its territory, and the facilities have existed for years.” 

In an editorial, the official Global Times newspaper added: “Defensive weapons were deployed on the island in the past. Even if the presence of the HQ-9 system is true as the West has claimed, it is a matter of China's sovereignty and it is fully legitimate for China to do so.” The article also suggested there was a difference between installing such systems on Woody Island — which has been under Chinese control for four decades, and where it said "sovereignty is not disputed" — and on other islands China has reclaimed on tidal reefs in the nearby Spratlys or Nansha chain over the past two years. The reclaimed islands have been the centre of massive controversy, since they are in an area claimed by the Philippines, Vietnam, and four other countries, and the Global Times acknowledged that “disputes over the sovereignty of islands in Nansha are sharp.”

The defense ministry dismissed foreign media reports as “hype” and a “rehash of the 'China threat.'"  And the Global Times, in its editorial, also rejected comments by Admiral Harry Harris, head of the U.S. Pacific Command, Wednesday that such moves were a breach of  pledges China made during a summit between President Xi Jinping and President Obama in Washington in September not to “militarize” the South China sea.

“The deployment of defense systems is not in the domain of militarization, as militarization of islands often means they are built into a fortress to become an outpost of military contests,” the paper said.

U.S. Secretary of State John Kerry said Wednesday that there had been “an increase of militarization of one kind or another in the region." He said this was “of serious concern,” and there would be a "very serious conversation” with China on the issue in the near future. 

One Beijing-based naval expert told the Global Times, however, that the issue was being "hyped" in the U.S. "to make more trouble in the region, so that the U.S. can deploy its forces and get further involved."   

The Global Times editorial said, however, that it was the U.S., “an outsider," that had “injected the most military elements in the region,” through plans to reopen military bases in the Philippines, and by basing “offensive nuclear submarines and various missile systems which are aimed at deterring China” at Guam in the Pacific. And it described last month’s freedom of navigation operation, in which a U.S. destroyer sailed within what China says are its territorial waters around Triton Island, another part of the Paracels Chain, as “the biggest act of militarization.”

It said China “currently” did not feel it necessary “to militarize the islands to cope with the other South China Sea claimants," but added that “uncertainties in the future come from the U.S. side. … Facing more frequent provocations from the U.S. military, China should strengthen self-defense in the islands in the South China Sea.” 

Some analysts say Beijing may have been planning for some time to build up its military facilities on the islands as part of a more assertive foreign and defense policy pushed by President Xi Jinping. But some observers also argue that China was particularly alarmed by the recent Triton mission, since it was close to an island the country has occupied for many decades, rather than one of the newly reclaimed islands as was the case in previous U.S. naval missions late last year.

Leading Chinese international relations specialist Jin Canrong, of Renmin University in Beijing, told the South China Morning Post that the deployment of missile systems on Woody Island was a “direct response” to the Triton patrol. He said the degree of build-up of military self defense facilities on the islands “depends on how much of a threat we feel we’re under,” though he said such developments were less likely on the more contested Spratlys chain as such moves “could backfire more severely.” Another expert quoted by the paper also said Beijing felt less confident about taking such action in the Spratlys, as they were further away and contested by six nations rather than just two, as in the case of Woody Island. 

Wu Shicun, of the National Institute for South China Sea Studies, told the paper that Beijing had reassessed security in the region following the US patrols.

“The assessment is that security is not ensured, and that the existing facilities in the island chains are not effective to protect safety there, so China has to enhance its defense capabilities,” he said.

And the South China Morning Post also quoted another Chinese naval researcher as saying that while air defense was the main priority, anti-ship missiles might also be considered for deployment in the region, depending on “the level of provocation from the U.S. and other non-claimant powers, and our own needs.”

Willy Lam, a specialist on Chinese politics at the Chinese University of Hong Kong, told international Business Times Wednesday that Beijing may have also brought forward the missile deployment to express its irritation at this week’s meeting between the U.S. and leaders of members of the Association of Southeast Asian Nations in California, at which the South China Sea was discussed — and after which President Obama stressed that freedom of navigation missions would continue. 

Lam said the deployment could also have been designed to express dissatisfaction at the proposed deployment of the U.S.-developed THAAD missile defense system in South Korea, in response to North Korea’s nuclear test in January and rocket launch earlier this month. Washington and Seoul are expected to discuss the proposal this week. 

Chinese experts have said the THAAD system would target Beijing’s defenses as well as those of North Korea. One Chinese analyst, writing in the Global Times Thursday, warned the system could spark a “destructive arms race” in Northeast Asia. Zhao Lixin said if THAAD were deployed, “China’s strategic missile force along the eastern coastline and 1,000 kilometers into the territory will be revealed and China’s offensive capabilities will be crippled,” with particular damage to China's ability to put pressure on Taiwan, which it claims as part of its territory. Zhao said China would have to respond by enhancing its ability to “counter disrupt and destroy the missile defense system.”