China blocks Philippines access to South China Sea reef

Satellite images reveal the extent of a Chinese blockade to prevent the Philippines supplying its base on Second Thomas Shoal, write John Pollock and Damien Symon.

The World Today Published 2 February 2024 Updated 21 March 2024 2 minute READ

Damien Symon

Geo-intelligence researcher, The Intel Lab

Satellite images recently released by Maxar reveal the extent to which tensions continue to rise in the South China Sea between the Philippines and China over a strategically important reef. Chinese coastguard vessels are shown blocking access to a Philippines military base on the reef, known internationally as Second Thomas Shoal and by China as Rén’ai Jião.

Second Thomas Shoal – which lies within the Philippines’ Exclusive Economic Zone 200km west of the archipelago and 1,000km from the nearest Chinese landmass – has been occupied by the Philippines since the 1990s. But the reef, which Manila calls Ayungin Shoal, has been a flashpoint for a decade, as Beijing continues its campaign to assert territorial control over the South China Sea.

Dramatic show of force

Tensions rose sharply in December 2023 when the Philippines undertook an operation to reinforce and resupply a contingent of its marines stationed aboard the BRP Sierra Madre, an ageing tank-landing ship that the military deliberately ran aground on the reef in 1999 to serve as a base. In a show of force, some 11 Chinese coastguard and maritime militia vessels were seen within the lagoon intercepting supply missions to the Sierra Madre.

Satellite image of Second Thomas Shoal in South China Sea, noting a Philippines vessel in the reef and the presence of many Chinese vessels

Second Thomas Shoal, November 2023
Chinese coastguard and other ships, seen here as white dots to the east of the reef, reportedly used water cannon and blocking tactics in a failed attempt to prevent a Philippine vessel from resupplying the BRP Sierra Madre. The inset detail reveals three Chinese maritime militia vessels around a Philippines Navy vessel. ©2024 Maxar Technologies.

The ship and its contingent of marines remains surrounded in contested waters with aircraft the only means of resupply. China’s aim, it appears, is to isolate the base and force a withdrawal by the Philippines.

We will never abandon [Second Thomas] Shoal. We will continue to resupply troops in the grounded vessel as long as it takes.

Spokesman for the Philippines national security council, August 2023.

These clashes follow an incident in February 2023 when the Philippines coastguard accused a Chinese coastguard vessel of deploying a ‘military grade laser light’ against one of its vessels. Since August, coastguard vessels from both countries have clashed several times. Manila has repeatedly accused China coastguard cutters of ramming Filipino vessels and turning water cannon on ships bound for the reef.

 

A spokesman for the Philippines National Security Council said in August: ‘China is trying to gauge our commitment to supply our troop. We will never abandon Ayungin Shoal. We will continue to resupply troops in the grounded vessel as long as it takes.’

satellite image of Philippines military vessel BRP Sierra Madre aground on Second Thomas Shoal, South China Sea

Second Thomas Shoal, November 2023
The BRP Sierra Madre was deliberately run aground in 1999 by the Philippines Navy to maintain the Philippines’ territorial claim on Second Thomas Shoal. The rusting 328ft-long ship is home to a detachment of Filipino marines. Access to the ship by sea has been prevented by a China coastguard blockade. ©2024 Maxar Technologies.

At the same time, the Chinese foreign ministry alleged the Philippines had repeatedly broken promises to remove its base from the reef. ‘The Chinese side once again urges the Philippines to immediately tow away the “stranded” warship from the Rén’ai Reef and restore the status of no one and no facilities on the reef,’ it said.

In 2016, the Permanent Court of Arbitration in the Hague dismissed China’s claims to sovereignty over Philippines waters.

If the Sierra Madre fell into the sea, the Chinese would almost certainly occupy the reef.

Bill Hayton, associate fellow, Asia-Pacific Programme, Chatham House

In the new satellite images, Chinese coastguard vessels, among the largest in the world, can be seen operating near the Sierra Madre in November 2023. Other images from September show Chinese vessels moored around the reef preventing passage to the lagoon. Images show large numbers of Chinese boats, thought to be maritime militia vessels, moored in waters near Mischief Reef and Union Banks, Chinese-controlled atolls next to the reef.

‘China wants to prevent the Philippines from reinforcing the hulk of the Sierra Madre,’ says Bill Hayton, associate fellow with the Asia-Pacific Programme, Chatham House. ‘The structure is at risk of falling into the sea and, if it does, the marines will have to leave. The Chinese would then almost certainly occupy the reef.’

According to some, Beijing is pressuring the Philippines to give up its commitments to the US under the Enhanced Defence Cooperation Agreement. ‘Even if the Philippines did agree, I don’t think China would back down,’ said Hayton.

A proxy for America

Sebastian Strangio, Southeast Asia editor of The Diplomat, said: ‘The Philippine pivot back towards America has only confirmed the prevailing Chinese view that the Philippines is something of a proxy for America, and that its relationship with America is premised on a China containment strategy.’

In 2012, Chinese coastguard vessels deployed similar tactics to contest the Philippines’ claim to nearby Scarborough Shoal. The Obama administration orchestrated a mutual withdrawal, but the Chinese coastguard continued to block access for Filipino fishing boats to the waters, and still does.

Satellite image of the Philippines base , BRP Sierra Madra, on Second Thomas Shoal, South China Sea

Second Thomas Shoal, November 2023
The Philippines base on the reef, BRP Sierra Madre, is marked. A Chinese coastguard cutter is visible to the north-west (see image below marked ‘detail’). ©2024 Maxar Technologies.

Over the past decade, China has increased pressure on claimant states of territories in the South China Sea, notably the Philippines and Vietnam. Attention has been directed towards Chinese military bases built on reclaimed islands, as well as on the growing fleet of warships fielded by the People’s Liberation Army Navy.

The relative weakness of the Philippines’ forces and the sheer number of Chinese vessels suggest that Second Thomas Shoal will continue to be a flashpoint in 2024.

Satellite image of a Chinese coastguard vessel in vicinity of Second Thomas Shoal, South China Sea

Second Thomas Shoal, November 2023 (detail)
A China coastguard cutter to the west of the reef. ©2024 Maxar Technologies.

Satellite image of Second Thomas Shoal in South China Sea reportedly showing two Chinese vessels

Second Thomas Shoal, September 2023 
A pair of suspected Chinese vessels operating in the vicinity of the reef. ©2024 Maxar Technologies.

Satellite image showing a fleet of suspected Chinese maritime militia fishing vessels moored to one another at the Chinese-controlled Mischief Reef, about 30km west of Second Thomas Shoa

Mischief Reef, September 2023 
A fleet of suspected Chinese maritime militia fishing vessels moored to one another at the Chinese-controlled Mischief Reef, about 30km west of Second Thomas Shoal. ©2024 Maxar Technologies.

Satellite image showing fleet of suspected Chinese maritime militia fishing vessels moored at Union Banks 150m west of Second Thomas Shoal

Union Banks, September 2023
A fleet of suspected Chinese maritime militia fishing vessels moored at Union Banks, a reef 140km west of Second Thomas Shoal. ©2024 Maxar Technologies.