Crushed coral and shipwrecks: Behind a new flashpoint in the South China Sea

A new flashpoint has emerged in the ongoing maritime dispute between China and the Philippines, with both countries clashing over yet another spot in the South China Sea.

Both China and the Philippines have staked their claims on various islands and zones in the Sea - their dispute increasingly escalating over the years with more vessel collisions, scuffles, and allegations of armed threats.

But last week, things came to a head when Beijing and Manila's vessels collided near the Sabina Shoal- both accusing the other of ramming them on purpose.

The shoal, claimed by China as Xianbin Jiao and as Escoda Shoal by the Philippines, is located some 75 nautical miles from the Philippines' west coast and 630 nautical miles from China.

On 19 August, several Chinese and Philippine vessels collided near the shoal in the disputed Spratly Islands - an area rich in oil and gas, which has been claimed by both countries for years.

The Chinese coast guard said that the Philippine vessel "deliberately collided" into them, while the Philippines said the Chinese vessels were conducting "aggressive manoeuvres".

A second round of collisions took place on Sunday, with both sides once again blaming each other. Several other countries including the UK, Japan, Australia and South Korea, as well as the EU, have criticised China's actions.

On Monday, the Philippines said 40 Chinese ships prevented two of their boats from conducting a "humanitarian mission" to restock the Teresa Magbuana, a Philippine coast guard ship deployed months earlier to the shoal.

The Philippines suspects China is attempting to reclaim land at Sabina Shoal. It has pointed to a nearby underwater mound of crushed coral, which its coast guard filmed, as evidence of such plans. Chinese state media has called this accusation "groundless".

Authorities sent the Teresa Magbuana to Sabina in April as part of a prolonged presence they plan to maintain at the shoal. Manila sees it as key to their efforts to explore the Spratlys for oil and gas.

China meanwhile sees the presence of the Teresa Magbuana as evidence of the Philippines' intentions to occupy the shoal.

A recent commentary by Chinese state news outlet Xinhua pointed to a decrepit World War Two era ship grounded by the Philippines in 1999 on the Second Thomas Shoal, known in Chinese as the Ren'ai Jiao.

A handful of soldiers are still stationed there and require regular rations. For years, the ship has been a source of constant friction between both countries, with China routinely attempting to block re-supply missions to the ship.

"25 years on, it is still there. Clearly, the Philippines is attempting to repeat this scenario at Xianbin Jiao," said the commentary.

"China will never be deceived by the Philippines again."

There has been a string of dangerous encounters in recent months as the two sides sought to enforce their claims on disputed reefs and outcrops, including the Second Thomas Shoal and the Scarborough Shoal.

The collisions usually arise from the cat-and-mouse games the boats engage in, as they attempt to chase the other side away.

China has increasingly blasted powerful water cannon and lasers at Philippine ships, with the Filipinos also accusing the Chinese of boarding their boats, leading to scuffles, as well as confiscating items and puncturing their inflatable vessels.

One of the latest accusations from Manila was that Chinese coast guard personnel armed with knives, spears and swords had boarded one of their military ships and threatened their soldiers.

So far there have been no fatalities, though the Philippines says several of its soldiers have sustained injuries. But President Ferdinand Marcos Jr has warned that any Filipino deaths resulting from China's actions would be considered an "act of war".

Observers worry their dispute could eventually spark a larger confrontation in the South China Sea.

Both countries have made an attempt to de-escalate the situation.

Last month they agreed to allow the Philippines to restock the outpost in the Second Thomas Shoal with food, supplies and personnel. Since then this has taken place with no reported clashes.

The incidents at Sabina Shoal however raise the question of whether such détentes are effective when the dispute can simply shift to a new site.

Additional reporting by Ian Tang