The Chinese military could soon deploy a high-altitude spy drone that travels at least three times the speed of sound, according to a leaked U.S. military assessment, a development that would dramatically strengthen China’s ability to conduct surveillance operations.

A secret document from the National Geospatial-Intelligence Agency, which has not previously been reported, shows the Chinese military is making technological advances that could help it target American warships around Taiwan and military bases in the region.

The document features satellite imagery dated Aug. 9 that shows two WZ-8 rocket-propelled reconnaissance drones at an air base in eastern China, about 350 miles inland from Shanghai. The drones are a cutting-edge surveillance system that could help China gather real-time mapping data to inform strategy or carry out missile strikes in a future conflict.

The assessment says the People’s Liberation Army (PLA) had “almost certainly” established its first unmanned aerial vehicle unit at the base, which falls under the Eastern Theater Command, the branch of the Chinese military responsible for enforcing Beijing’s sovereignty claims over Taiwan.

The Washington Post obtained the assessment of the WZ-8 program from a trove of images of classified files posted on Discord, a group chat service popular with gamers, allegedly by a member of the Massachusetts Air National Guard.

The Defense Department declined to comment. China’s Ministry of National Defense did not respond to a faxed request for comment.

Other documents in the trove detail a number of disclosures about Chinese spying and military modernization, including intelligence that revealed the existence of additional Chinese spy balloons and an assessment that Taiwan is ill-prepared to prevent early Chinese air superiority during an invasion.

This latest revelation about the advancement comes as intensifying military aggression around Taiwan has heightened concern about a Chinese invasion on the self-governed island democracy.

CIA Director William J. Burns has said Chinese leader Xi Jinping wants the PLA to be capable of seizing Taiwan by 2027, although he added that this does not mean Xi will order an attack at that time.

Beijing introduced the WZ-8 drones in 2019 when two of the jet-black aircraft were paraded past Tiananmen Square during celebrations for the 70th anniversary of the establishment of the Communist Party-run People’s Republic of China. Few analysts considered the drones fully operational at the time.

Also included in the National Geospatial-Intelligence Agency’s assessment are possible flight paths for the drone as well as for the twin-engine H6-M Badger bomber used to launch it. After taking off from its home air base, the warplane would fly to just off China’s east coast before releasing the stealthy drone, which could then enter Taiwanese or South Korean airspace at a height of 100,000 feet and fly three times the speed of sound. The document does not detail how the drone is propelled but says “engine features are primarily associated with rocket fuel.”

A map of projected routes, labeled “not necessarily authoritative,” suggests ways the drone’s “Electro-optical” cameras and sensors could gather intelligence on Taiwan’s main island and the western side of South Korea including Seoul, the capital city. The use of synthetic aperture radar would allow it to map territory at night and foggy weather.

The drone’s primary use won’t be against Taiwan but against the United States and its military bases in the Pacific, said Chi Li-pin, director of the aeronautical systems research division at the National Chung-Shan Institute of Science and Technology, Taiwan’s military-run weapons developer. “It’s a weapon for anti-access and area denial,” he said.

Chi added that the aircraft does not currently appear to be designed to launch attacks, but he noted modifications could allow it to conduct strikes in future. “It is difficult to detect and intercept. The existing U.S. air-to-air weapons aren’t good enough,” he said.

Dean Cheng, a nonresident senior fellow with the Potomac Institute for Policy Studies, said the disclosure shows China is developing a capability to monitor the entire Indo-Pacific region. “This is not just aimed at the United States or South Korea,” said Cheng, who had not seen the documents. “Japan has to worry about it. India has to worry about it. All Southeast Asia has to worry about it.”

China, he noted, is creating a range of high-tech systems for military use — from hypersonic weapons that can use drone reconnaissance for anti-ship purposes to antisatellite weapons that they could use to try to blind the United States. “Individually, none of these things are game-changers,” he said. “Taken together, we’re looking at a PLA that is developing a reconnaissance strike complex: Find the enemy, hit the enemy, kill the enemy.”

The airfield described in the document as “Liuan” appears to be a base in Dushan County of Lu’an city, according to coordinates in the document. (The first Chinese character in Lu’an is often pronounced ‘liu’ but it is ‘lu’ in this instance.)

It was originally built in 1970, part of leader Mao Zedong’s campaign to move crucial industries and military installations into mountainous regions, prompted after relations with the Soviet Union soured and left China’s communist leadership feeling vulnerable to attack. The hangars of the original air base, known then as the 8301 airfield, were burrowed into the hillside and had steel-plated doors that were 12 inches thick, according to Chinese state media.

A review of satellite imagery publicly available on Google Earth and provided to The Post by Planet Labs shows the base has expanded multiple times in recent years, with at least 18 new structures constructed after August 2020. Beginning in late February 2022, new, significantly wider thoroughfares that lead into the hills south of the runway were constructed. In some places, the new clearing is about 130 feet wide.

Enthusiasts who use open-source material to track the Chinese air force believe the base is home to a regiment of the Eastern Theater’s 10th bomber division, the branch most likely to conduct air attacks if China launches a full-scale assault on Taiwan.

Joseph Wen, a Taipei-based independent analyst who tracks military installations in China, says that the base was abandoned for years. It was even used as a filming location for a patriotic action film about the Sino-Japanese War.

But there have been clear signs since 2019 that the base has been brought back into service. Wen has tracked a flurry of construction activity, included widening the paths that lead to the southern cavern entrance to nearly 130 feet. The wingspan of the bomber plane used to launch the drone is 108 feet.

The Washington Post’s Meg Kelly contributed to this report.

previous coverage

• ‘You’re ignoring the law’: Navy secretary grilled in Senate over lack of amphibious ships
• Taiwan to buy 400 US anti-ship missiles intended to repel a China invasion
• Navy sends destroyer through Taiwan Strait less than a week after Chinese exercises
• Taiwan highly vulnerable to Chinese air attack, leaked documents show