China has denounced interpretations of its military operations in the East and the South China Sea contained in a new US Defense department report that spotlights cyber warfare.
The report "deliberately distorted" China's defence policy and legitimate actions, spokesman Yang Yujun said in a statement posted on Saturday on the Chinese defence ministry's official feed on Weibo, the popular Chinese microblogging site.
At issue is the Defence Department's annual report to Congress on China's capabilities, published on Friday. China typically responds sharply to the US assessments. The 156-page document was released ahead of a visit to Vietnam and Japan this month by President Barack Obama amid increasing tensions between the US, China and Southeast Asian nations over sovereignty claims in the South China Sea.
The report asserts that China's military conducted cyber probes and intrusions against US computer networks to support intelligence collection and electronic warfare.
"China is using its cyber capabilities to support intelligence collection against the US diplomatic, economic, and defence industrial base sectors that support US national defence programmes," the defence department said in the report.
Highlighting what the Pentagon describes as China's focus on improving cyber capabilities to counter a "stronger foe", the report said information gleaned by hackers "could inform Chinese military planners' work to build a picture of US defence networks, logistics, and related military capabilities that could be exploited during a crisis".
"The accesses and skills required for these intrusions are similar to those necessary to conduct cyber attacks," according to the report. The intelligence gathering could also provide the ruling Communist Party "insights into US leadership perspectives on key China issues."
Yang, the Chinese defence ministry spokesman, warned in response that China wants the US to stop using words or actions detrimental to maintaining mutual trust between the US and Chinese militaries.
In the same statement, Yang said that China is reinforcing its military along defensive lines, to protect its sovereignty, security and territorial integrity. And the artificial islands being built in the South China Sea are mostly for civilian needs, said Yang.
The Pentagon report said that President Xi Jinping's military in 2015 "accelerated land reclamation and infrastructure construction at its outposts in the Spratly Islands", which when complete "will include harbors, communications and surveillance systems, logistics facilities, and three airfields".
"Although artificial islands do not provide China with any additional territorial or maritime rights within the South China Sea, China will be able to use its reclaimed features as persistent civil-military bases to enhance its presence in the South China Sea significantly and enhance China's ability to control the features and nearby maritime space," the report said.
China claims more than 80 per cent of the South China Sea. Several other nations, including Vietnam and the Philippines, have competing sovereignty claims in the region.
Adding to tensions, Chinese naval vessels followed and sent warnings to the USS William P Lawrence this week as the vessel sailed within the 12 nautical mile (22 kilometre) territorial zone around Fiery Cross Reef, a feature in the Spratly Islands where China has dumped hundreds of thousands of tons of sand and coral to create an island on which it has built an airstrip.
China called the US warship's manoeuvres "a naked challenge," while the US said it was a "freedom of navigation" operation in international waters, one of many it has taken near contested reefs and outcrops.
Chinese officials held a video conference on the tensions on Friday with Marine General Joseph Dunford, chairman of the US Joint Chiefs of Staff.
The Pentagon's report also highlighted what it described as an "extraordinarily rapid" expansion of China's long-range precision strike capabilities. While China has a no-first-use policy toward nuclear weapons, the report suggested -- based on Chinese media reports and military writings - that the country intends to build a stealth bomber to carry nuclear weapons.
"If it does, China would develop a 'triad' of nuclear delivery systems dispersed across land, sea and air - a posture considered since the Cold War to improve survivability and strategic deterrence," according to the report. The US has plans to modernise its long-standing nuclear triad.
One of the Chinese military capability developments being most closely watched is when its first JIN-class submarines start to said armed with JL-2 intercontinental ballistic nuclear missiles capable of striking the US. These patrols have been forecast for at least two years in the Pentagon report and in Defence Intelligence Agency congressional testimony.
According to Friday's assessment, "this platform represents China's first credible, sea-based nuclear deterrent." US Deputy Assistant Secretary for East Asia Abraham Denmark told reporters on Friday that China has not yet conducted a "deterrence" patrol.
"China will probably conduct its first" nuclear-missile armed submarine patrol sometime in 2016, the report said.