Tensions have been mounting between the Philippines and China in the South China Sea, one of the world's most important trade routes.

The yearslong dispute centers around Second Thomas Shoal, called Ayungin Shoal by the Philippines, which is part of a group of islets and shoals called the Spratly Islands.

Second Thomas Shoal is in an area militarily occupied by the Philippines but claimed by several countries, including China.

In 1999, the Philippines purposely ran aground a World War II warship, the BRP Sierra Madre, on the reef — leaving it manned with a handful of marines to reinforce its claim on the territory, which it considers part of the Philippines' exclusive economic zone.

When Philippine vessels resupply troops at the shoal, they have often faced aggressive encounters from Chinese ships.

Tussles on the high seas

In the past year, the Philippine coast guard has accused China's coast guard of shining a "military-grade laser light" at one of its ships, firing a water cannon and ramming Philippine vessels near the disputed shoal.

More recently, in December, as Philippine ships carried out their monthly "rotation and resupply mission" to the Sierra Madre, China responded with an overwhelming show of force, sending 11 Chinese coast guard or maritime vessels to block the operation.

But Aries Arugay, a visiting senior fellow at the ISEAS-Yusof Ishak Institute in Singapore, said Manila under President Ferdinand Marcos Jr. is continuing to do what it believes is right.

"The Marcos administration just doesn't care anymore about how China reacts, because China will always give cookie-cutter responses. It's the same spiel and it's getting old," he added.

The Philippines' firm stance over the dispute with China has since emboldened Manila, which is bolstering its national security efforts.

In January, Philippine military chief of staff General Romeo Brawner Jr. confirmed that Manila was shifting its focus from internal defense to territorial defense.

And Defense Secretary Gilberto Teodoro Jr. has ordered the military to increase troops on the Batanes Islands, a Philippine archipelagic province close to Taiwan.

Is Manila 'stoking the flames' with Beijing?

Under a joint defense agreement, American troops have been granted access to more of the Philippines' military bases, and joint patrols in the South China Sea took place last month.

The Philippines has also conducted patrols with Australia and has plans to collaborate with the UK, France, Canada, India, Japan and New Zealand in similar operations.

Beijing has accused Manila of "stoking the flames," but Arugay said most people living in the Philippines support the country's position in the territorial dispute with China.

"Except for a few disgruntled retired military officials who have interest in maintaining ties with Chinese business, much of the security sector, the active ones, are lauding, if not are truly behind this approach of democracy," said Arugay.

And, according to two surveys by OCTA Research, the majority of Filipinos approve of boosting military cooperation with the US and want Manila to solve its disputes by diplomacy.

Tensions thawing

In January, foreign ministers from Manila and Beijing agreed to improve communications and manage their differences diplomatically, a strategy that seems to be working.

The Philippines' first supply mission of 2024 to the shoal was deemed as "flawless," according to Colonel Francel Padilla, the spokesperson for the Philippines Armed Forces.

China claimed they had "allowed" the resupply to the shoal — which they referred to as a "special arrangement" — but Manila rejected Beijing's position, saying it has the right to supply its own troops.

Colonel Ray Powell, of Stanford University's Gordian Knot Center for National Security Innovation, said the successful resupply shows that Beijing has reduced its aggressive approach since the talks.

"That last resupply mission to the Second Thomas Shoal was barely opposed. Philippines, when it was done, described it as perfect, which they mean that nothing really happened," Powell told DW.

"I think essentially there was an agreement that if you guys don't put everything out on the internet, then maybe we can all lower the tensions."

Under former President Rodrigo Duterte, complaints about Chinese intimidation of Philippine vessels in the South China Sea were neither raised publicly nor fed to the media.

But that policy has changed under President Marcos Jr., with Manila being more vocal about the encounters with Chinese maritime ships.

Powell said the persistence from Manila has been so far successful.

"I looked at it as kind of a victory for the Philippines because it means their transparency initiative actually gave them leverage. It's clear that China does not like pictures," he said.

"And so, the Philippines has stuck with it long enough to demonstrate that they're willing to sort of hold on to this tool until they get something in return," he said, adding that Manila appears to have been successful in getting the Chinese to back off. 

Edited by: Keith Walker