Inside the Ring: China imposes 40-day airspace restriction near coast

NEWS AND ANALYSIS:

The Chinese government recently announced an unusual 40-day air exclusion zone off the coast of Shanghai without explanation.

The restricted airspace was announced in an alert called a notice to airmen that usually precedes Chinese military exercises or missile test firings.

However, the alert offered no reason for exclusion zone that lasts from March 27 through May 6 and covers an area some 340 miles in five zones.

Military analysts say the air exclusion zones are likely a signal that China will conduct large-scale military exercises.

So far, no exercises have been announced, leading some analysts to speculate that China could be preparing for military action at a time when the U.S. is engaged in a war against Iran.

Retired Navy Capt. Jim Fanell said the closure zones “are more likely to be related to an upcoming exercise like the previous Justice Mission Exercises.”

The large-scale, saber-rattling Justice Mission Exercises were held most recently in December and involved provocative and threatening drills with naval and air force maneuvers all around Taiwan.

Rick Fisher, a China expert with the International Assessment and Strategy Center, said a 40-day People’s Liberation Army exercise would give the Chinese military an opportunity to practice high operations tempo or sustained operations for its planned Taiwan invasion. “The location of the restricted areas would serve to better block U.S. forces transiting from South Korea to a Taiwan area of operations,” he said. 

The air zone closure notice stated that the ceiling for civilian aircraft warned to avoid is unlimited, known to pilots as by the designation SFC-UNL.

“What makes this especially notable is the combination of SFC-UNL with an extraordinary 40-day duration — and no announced exercise,” Ray Powell, director of the SeaLight project at Stanford University, which tracks Chinese maritime activity, told The Wall Street Journal.

“That suggests not a discrete exercise but a sustained operational readiness posture — and one that China apparently doesn’t feel the need to explain,” he said.

In the past, Chinese notice to airmen lasted for several days.

The zones for the closure areas include air and water areas in the Yellow Sea facing South Korea, south through the East China Sea near Shanghai, and toward waters near Japan.

Japan has become a major target of Chinese propaganda in recent weeks following Tokyo’s announcement it has deployed 620-mile-range missiles.

The unusual air closure zones follow China’s sharp curtailment of military flights around Taiwan last month.

For 10 days, no warplanes from the PLA air force were detected after nearly two years of regular incursions near the self-ruled island and rival to China.

Flights by PLA aircraft resumed March 16.

Mr. Powell said if exercises are held in the coming days, the alerts would be “a meaningful shift in how Beijing uses airspace control as a tool of military signaling.”

Taiwan officials have said they suspect China will step up military activity along the coast as the Trump administration is distracted by the conflict in the Middle East.

The exclusion zones are “clearly aimed at Japan” in a bid to deter American allies and weaken military influence, one official said.

The closure zones cover a period before President Trump’s visit to China on May 12.

A PLA unit in charge of the East China Sea and Taiwan Strait conducted a decontamination exercise simulating a response to a nuclear attack, China state television reported Tuesday.

The time and location of the drill was not disclosed.

The exercises involved rapid detection and decontamination in areas where troops were operating, CCTV reported.

The Eastern Theater Command drill deployed troops involved in chemical, biological, radiological and nuclear defenses using drone helicopters with traditional handheld radiation detectors to rapidly identify the scope and boundary of the contaminated zones.

Trade rep says Trump looking for deal with China

U.S. Trade Representative Jamieson Greer, who is closely involved in preparations for Mr. Trump’s May visit to Beijing, said the United States is not looking for any fights with China.

Mr. Greer said during remarks Tuesday that economic and trade ties with China are “stable,” adding that the description may be boring but “that’s what it is right now.”

“What we are not looking for is massive confrontation or anything like that,” he said during a meeting at the Hudson Institute. “At the same time, we have to protect our national security. We have to protect our economic security.”

The results so far are a stable situation with China that includes substantial U.S. tariffs remaining in place on Chinese goods, mainly on advanced technology and manufacturing, he said.

“And this is not really in the nature of wanting to, again, have a fight with the Chinese or anything, but we have a domestic challenge with respect to our huge trade deficit that’s exploded,” he said.

Mr. Greer said the U.S. trade deficit with China declined by $130 billion last year.

On the upcoming presidential summit in Beijing, the U.S. will seek to maintain stability and “ensure we can continue to get rare earths from the Chinese,” he said.

Trade talks with Chinese officials in Paris led by Mr. Greer and Treasury Secretary Scott Bessent raised the issue of rare earths, the trade representative said.

China shocked the Trump administration last year by imposing sharp restrictions on the exports of rare earth minerals that U.S. industry needs.

The curbs were retaliation by Beijing for steep U.S. tariffs on China targeting fentanyl and related exports and other unfair trade practices.

The rare earth restrictions led to a major shift in Mr. Trump’s stance toward China. Since the rare earth limits were imposed first in April and tightened in October, the president sharply toned down both rhetoric and criticism of China.

Instead, Mr. Trump has resorted to praising Chinese President Xi Jinping and repeatedly stressing his close ties him.

Mr. Greer said discussions in Paris included the idea of creating a U.S.-China board of trade.

“We’re looking at that kind of mechanism where we can work with the Chinese to figure out what are the nonsensitive goods we should be trading with each other [and] get a handle on that, figure out what those flows should look like, and then you’re in a better position to talk about stickier issues,” he said.

The topic of Chinese control over rare earths is a central issue in trade relations and resolving the problem could be solved before Mr. Trump meets Mr. Xi, Mr. Greer said.

“But of course, the president, as he has in the past, he will continue to advocate for U.S. access to rare earths with the Chinese and with President Xi,” he said.

Since the Chinese restrictions, the U.S. has taken major steps toward self-sufficiency in producing rare earth minerals through cooperation with other nations, stockpiling key elements and developing mining, processing, refining, and manufacturing facilities, he said.

NSA, Australians warn Starlink can be hacked

Four government security agencies are warning that low-Earth orbit satellite communications such as SpaceX’s Starlink system are vulnerable to hostile cyber hacking operations.

A report published Wednesday by the Australian Signals Directorate, the government signals intelligence and security agency, warns that low-Earth orbit, or LEO, communications system face an array of cyber threats to their networks.

“These networks face a range of risks,” states the report produced with the National Security Agency and security agencies in Canada and New Zealand.

The NSA said in a social media post that all organizations using satellite communications are urged to take steps to mitigate “the unique cybersecurity challenges these systems face.”

Cyberattackers can gain unauthorized access to data transmitted between satellites and ground stations or between satellites. A hacker can also manipulate telemetry, mission data or logs and steal data from compromised ground station storage systems, the report said.

The main company currently engaged in commercial satellite service is Starlink. The SpaceX company has deployed thousands of LEO satellites that provide high-speed internet service to more than 150 nations.

Attackers may exploit vulnerabilities in orbiting satellites’ command and control channels from poor encryption and authentication, the report said.

Other dangers include signal spoofing, malware injection and memory corruption through hackers’ imposing faulting data.

“The space segment, comprising the satellites themselves, faces unique cyber threats due to its critical role in satellite communications,” the report said.

A Starlink spokesman did not immediately respond to an email request for comment.

The report did not identify nations engaged in planning cyber operation against satellites.

However, western intelligence and cybersecurity firms have identified multiple cases of Chinese state-sponsored actors targeting satellite infrastructure.

A CIA document leaked online by an Air National Guard member in 2023 revealed that China is developing cyberweapons that can be used to “deny, exploit or hijack” enemy satellites.

The document said the capability will allow China “to seize control of a satellite, rendering it ineffective to support communications, weapons, or intelligence, surveillance, and reconnaissance systems.”

Chinese state cyber actors in an operation called Salt Typhoon in mid-2025 also targeted ViaSat, a major satellite internet provider for the U.S. government and military.

• Contact Bill Gertz on X @BillGertz.