News that a Chinese coast guard ship fired water cannon on a smaller Philippine counterpart in a disputed area of the South China Sea should be worrying enough, given the region is widely seen as a potential flashpoint for global conflict.
But look more closely at video footage of the incident and tucked away in the details is something arguably even more striking: some of the most compelling evidence yet, according to analysts, of the links between the Chinese military and an alleged maritime militia sometimes referred to as Beijing's "little blue men."
Footage supplied by the Philippines of last weekend's incident shows multiple Chinese vessels blocking its ship from supplying a remote military outpost on Second Thomas Shoal in the Spratly Islands. Most of the Chinese ships involved are marked "China Coast Guard," but among the flotilla are also at least two blue-hulled vessels that resemble fishing boats.
Western marine security experts -- along with the Philippines and the United States -- believe those boats belong to a Beijing-controlled maritime militia that experts say is hundreds of vessels strong and acts as an unofficial -- and officially deniable -- force that China uses to push its territorial claims both in the South China Sea and beyond.
The vessels are part of the same force, they say, that swarmed Whitsun Reef, another Philippine-claimed feature in the Spratlys, with up to 220 vessels in 2021.
"In this particular operation, we can actually conclude that this Chinese fishing vessel is not just a fishing vessel but a Chinese maritime militia taking orders from the Chinese coast guard to support their operations in blocking our resupply," Philippine Coast Guard spokesperson Jay Tarriela said at a briefing last week.
The latest incident came as the Philippines tried to resupply a contingent of marines it keeps on Second Thomas Shoal -- a feature of the Spratly Islands that has long been disputed between the two countries.
The remote shoal lies more than 620 miles from mainland China's southernmost shore and some 120 miles from the Philippine island of Palawan.
The Philippines grounded a World War II-era warship, the Sierra Madre, on the shoal in 1999 to assert its claim to sovereignty and now keeps its marines stationed on it, but the vessel's isolation and aging condition make it a relatively easy target to harass.
After the confrontation last weekend, China claimed the Philippines had violated its sovereignty by grounding the ship on the shoal.
"The Philippine side has repeatedly promised to tow away the 'grounded' warship, but 24 years have passed, and the Philippines has not only failed to tow away the warship but also attempted to repair and strengthen it on a large scale to achieve permanent occupation of the Ren'ai Reef," a China Coast Guard statement said, using the Chinese name for the shoal.
The action it took last weekend "was professional and restrained, which is beyond reproach," it said.
Chinese authorities did not respond to a CNN request for further comment on the issue.
The shoal is just one of many disputed features in the South China Sea, where Malaysia, Vietnam, Brunei and Taiwan also all have competing sovereignty claims. However, China's claims are by far the most expansive; it insists almost all of the 1.3 million square miles of the sea are its sovereign territory, despite a 2016 ruling by an international tribunal in the Hague denying those claims.
Over the last two decades China has occupied a number of reefs and atolls across the South China Sea, building up military installations, including runways and ports.
Western experts warn that the alleged militia -- with hundreds of boats allegedly funded and controlled by the People's Liberation Army -- is a force to be reckoned with. As the Whitsun incident showed, they say, it could be used to swiftly surround any disputed reef or island, acting either alone or in concert with the coast guard or the PLA Navy.
While the latest video is not the first time suspected militia vessels have been caught on camera, many experts believe it is one of the most compelling illustrations yet of how the Chinese military and the militia interact. That symbiotic relationship became even clearer in 2021 when the China Coast Guard came under the jurisdiction of the Chinese Central Military Commission effectively making it part of Beijing's military.
"There's no way they (China) can pull that operation off without it being pre-planned and there being real-time communication between the two," said Lyle Morris, a senior fellow at the Asia Society Policy Institute's Center for China Analysis and a former US defense official.
'Gray zone' tactic
China, for its part, doesn't acknowledge the existence of any such maritime militia. In the past, when questioned, it has referred to the ships as a "so-called maritime militia."
But Western experts say this deniability is part of the point.
Ray Powell, director of SeaLight at the Gordian Knot Center for National Security Innovation at Stanford University, said the militia helped China operate in the "gray zone," by carrying out actions just below what might be considered acts of war but that achieve the same result -- Beijing gaining territory or control without firing a shot.
Both Powell and Morris say what China is trying to do around the Second Thomas Shoal is essentially a blockade, a naval maneuver preventing free access to it.
The Chinese vessels "physically blockaded the supply ship. It's hard to deny that there is an actual blockade going on," Powell said.
An official blockade by the PLA Navy would be an act of war, the analysts point out. But by using the militia instead -- keeping things in the gray zone -- China keeps the operation below the level of a confrontation that might require a response under the US-Philippines mutual defense treaty, the analysts say.
Was this an own goal by China?
But Morris says evidence like the video released by the Philippine Coast Guard helps arguments in Washington, Manila and other foreign capitals that the maritime militia should be treated as a legal combatant.
"If (the US) can prove they are under the command of the China Coast Guard, which is under the command of the Central Military Commission," Washington can make the claim that this is an act that could trigger the mutual defense treaty, Morris said.
That could possibly lead to the US Navy or US Coast Guard playing a role in escorting future resupplies of the Philippine marines on Second Thomas Shoal.
However, Powell points out that neither Washington nor Manila may have the stomach for the increased tension that would likely result from a US presence in these operations.
"A blockade is an act of war. That term is so pregnant with implications that people in official positions are going to continue to be very circumspect about using it," he said.
China's waiting game
Analysts say they don't see any appetite in Beijing for actual combat over Second Thomas Shoal, but they also say China can afford to play a waiting game.
Lionel Fatton, an international relations professor at Webster University in Switzerland, says the shoal is a good spot for China to practice "gray zone" tactics and "demonstrate their capability of causing trouble in anticipation of greater US involvement in the area."
Washington is getting access to more military facilities in the Philippines, including on Balabac in Palawan province, not far from the shoal.
Meanwhile, as Powell points out, the condition of the Sierra Madre means it is the Philippines that is under pressure time-wise.
The Madre is a former US Navy tank landing ship built more than 70 years ago and slowly corroding away. Keeping it habitable isn't easy.
Indeed, doing so just got a little harder as the supply boat China prevented from reaching it last weekend had been carrying materials intended to shore it up.
"The Sierra Madre is visibly rusting away, it is becoming structurally unsound. At some point it will begin to breakup and otherwise become uninhabitable," Powell said.
"At which point China's strategy works because all they have to do then is sort of 'rescue' the poor Philippine sailors off the shoal because they're the only people around.
"And (then they will) control the shoal," Powell said.
"Unless something changes, that is what will happen. It's just a matter of when it will happen."