The United States has staged a simulated island assault exercise featuring a red silhouette of China on air personnel's uniforms, in what Chinese state media described as a provocative gesture.
The drill was being conducted in California, but triggered warnings from Chinese state media that China would fight back if the US attacked it in the South China Sea.
US-based Air Force magazine reported that the training by the US veteran drone fleet, which began on September 3, suggested that the US Air Force was focusing more on the Pacific region.
Patches on uniforms made for the exercise featured an MQ-9 Reaper drone superimposed over a red silhouette of China, the report said.
In the drill, Exercise Agile Reaper, three MQ-9s partnered with the US Navy's Third Fleet, which deployed carrier strike groups, submarines and other vessels and aircraft to the eastern Pacific, along with transport aircraft C-130s, and special warfare and Marine Corps personnel.
The reapers performed air strikes during a mock amphibious assault on San Clemente Island off the Californian coast.
"It's a demonstration of our capability to rapidly move the MQ-9 anywhere in the world, to unfamiliar locations, and then get out and show the operational reach capabilities of the MQ-9," US 29th Attack Squadron Commander Lieutenant Colonel Brian Davis told the magazine.
MQ-9 Reapers have been used in wars in the Middle East and Africa for two decades, but the US Air Force has considered replacing them over fears that their stealth, electronic protection and speed capabilities were falling behind those of more advanced drones produced by China and Russia, according to Air Force.
Despite the training exercise taking place far from the Chinese coast, China's state media suggested that the drones could be deployed to attack Chinese-built facilities in the South China Sea.
"Washington is stepping up preparations for war against China, and this type of drone that has participated in murders and other attacks around the world will also play a role in it," an editorial by nationalistic tabloid Global Times said on Monday. "This is the strategic signal sent from the exercise.
"This is to stir hostilities between the two countries, and is also a blackmail to China. Using such an armband with a Chinese map will stimulate people's imagination and create a picture of China and the United States going to war."
In August, retired Chinese naval officer Wang Yunfei suggested that the US might launch an attack on disputed Chinese-controlled reefs in the South China Sea to boost Trump's re-election prospects.
Wang said the most likely target of a sudden US attack would be Scarborough Shoal, known in China as Huangyan Island.
Song Zhongping, a Hong Kong-based military commentator, said although the US Air Force had the ability to mount a drone attack against Chinese entities in the South China Sea, it was unlikely because China would retaliate and the consequences would be huge.
Collin Koh, a research fellow from the S Rajaratnam School of International Studies at Singapore's Nanyang Technological University, agreed with Song, saying Reaper strikes against China's South China Sea outposts would have little impact on reinforced facilities such as the bunkers.
"[They] may cause some, but not too serious, damage to the other facilities especially the exposed ones," Koh said.
"What's the whole game plan in using a drone strike? The Chinese would remain firmly in control of the outposts, and the strike would then justify the PLA to further militarise them."
He added that a US strike would further undermine its credibility and hand a moral victory to Beijing in the South China Sea.