China’s military conducted cyber probes and intrusions against U.S. computer networks to support intelligence collection and electronic warfare, according to a new Pentagon report.

“China is using its cyber capabilities to support intelligence collection against the U.S. diplomatic, economic, and defense industrial base sectors that support U.S. national defense programs,” the Defense Department said in its annual report on China’s capabilities, published Friday.

The report, which traditionally draws a strong reaction from the Chinese government, comes ahead of a visit to Vietnam and Japan this month by President Barack Obama and amid increasing tensions between the U.S., China and Southeast Asian nations over sovereignty claims in the South China Sea.

Highlighting what the Pentagon described 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 U.S. defense networks, logistics, and related military capabilities that could be exploited during a crisis.”

Leadership Insights

“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 U.S. leadership perspectives on key China issues.”

In the South China Sea, President Xi Jinping’s military last year “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.”

QuickTake: Territorial Disputes Simmer Around an Assertive China

“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,” it said.

At least six nations, including China, Vietnam and the Philippines, have competing sovereignty claims in the South China Sea.

‘Naked Challenge’

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 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 U.S. warship’s maneuvers “a naked challenge.” The U.S. said it was a “freedom of navigation” operation in international waters, one of many it has taken near contested reefs and outcrops.

The report also highlighted what it described as an 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.

Nuclear Triad

“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 U.S. has plans to modernize its long-standing nuclear triad.

One of the most closely watched Chinese military capability developments is when its first JIN-class submarines go on patrol armed with JL-2 intercontinental ballistic nuclear missiles capable of striking the U.S. These patrols have been forecast for at least two consecutive years in the Pentagon report and in Defense Intelligence Agency congressional testimony.

According to Friday’s assessment, “this platform represents China’s first credible, sea-based nuclear deterrent.” U.S. Deputy Assistant Secretary for East Asia Abraham Denmark told reporters 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.