The issue was a matter of national sovereignty and transparency, she said.

In response, the US embassy to the Philippines said the shipment was coordinated with Manila and was “one of multiple shipments of safe, clean fuel”.

The US-registered tanker Yosemite Trader, which carried the fuel to the Philippines, later reportedly cancelled plans to discharge its cargo at Subic Bay.

Aaron Jed Rabena, senior lecturer at the University of the Philippines Asian Centre, said it was likely areas of the Philippines hosting a US military presence could be targeted by the People’s Liberation Army.

“The Chinese will likely be on the lookout for where US troops and military assets could come from and aid American troops on the front lines fighting in the South China Sea,” Rabena said.

“And as per the 1951 MDT [Mutual Defence Treaty], the Philippines is bound to help the US in the event of an armed attack on it anywhere in the Pacific.”

04:30

Philippines sets up ‘game changer’ monitoring station on island in disputed South China Sea

Philippines sets up ‘game changer’ monitoring station on island in disputed South China Sea

Zachary Abuza, a professor at the National War College in Washington who specialises in Southeast Asia, said the pre-positioning of jet fuel and other equipment in the nine Philippine facilities identified under the EDCA “invariably” made the Philippines a target for Beijing in any military conflict between the US and China.

“That is the risk borne by the Philippines in return for the US security commitment,” he said.

Collin Koh, a senior fellow at the S. Rajaratnam School of International Studies in Singapore, said the possibility of the PLA targeting US military fuel and equipment in the Philippines was “not just about a military question”.

“It is also about a political question: do [the Philippines] want to also draw in another potential belligerent?” he said.

Koh said the PLA could use it as a bargaining chip to tell the Philippines, “because we are not going to target [or attack] you … you know what to do. You shouldn’t support the US if you don’t want to be targeted.”

Do US military bases bring violence to the Philippines – and other countries?

The tensions between Beijing and Manila have recently increased, with Chinese and Philippine coastguards clashing near the Second Thomas Shoal of the disputed Spratly Islands in the South China Sea over Manila’s resupply mission to its troops stationed in the atoll.

The confrontation escalated after the Chinese coastguard blasted water cannons at Philippine vessels in August and Manila accused China of using them again in December. In other clashes, the two sides collided with each others’ ships.

The Chinese foreign ministry on Tuesday said Manila had “seriously violated political commitments made by the Philippines to China” and told Marcos to “read more books to properly understand the ins and outs of the Taiwan issue”.

Since Ferdinand Marcos Jnr rose to power in 2022, Manila has promoted stronger ties with the US and other like-minded countries.

On Thursday, its embassy in London announced the Philippines and Britain had signed a memorandum of understanding (MOU) on defence cooperation between the two countries.

The bilateral deal includes defence and military education and training, peacekeeping operations, humanitarian help and disaster relief, and armaments and military equipment acquisition.

Canada is reportedly sending its officials to the Philippines this week to discuss signing a similar defence cooperation MOU.

05:12

Philippines races to upgrade its degrading military in the face of maritime disputes

Philippines races to upgrade its degrading military in the face of maritime disputes

Manila held joint exercises with Australia in the South China Sea in August and upgraded bilateral ties with Canberra to a strategic partnership in September, agreeing to hold annual defence ministers’ meetings.

“This follows through on the series of enhanced bilateral security partnerships that the Philippines is pursuing with like-minded countries and traditional security partners … to help in the modernisation of the Philippine military and enlist their political and diplomatic support for the Philippines’ situation in the South China Sea,” Rabena said.

Abuza said Manila was restoring stronger ties with Washington and its allies that had been marginalised in the previous administration.

“The Philippines has tried to make up for its limited military capabilities by building up security partnerships, allowing rotational deployments and overflight,” Abuza said. “The alliance with the United States, which was so damaged under the presidency of Rodrigo Duterte, has been deepened.”

The South China Sea and Taiwan may be twin powder kegs, but which is riskier?

Abuza added that while the rising tensions in the South China Sea raised concerns for other claimants of the waterways – such as Vietnam and Malaysia – these countries would prefer not to escalate the tensions in the region, even if supporting the US-Philippine defence cooperation.

“While all of the claimants prefer to have the United States routinely deployed in the region and engaging in freedom-of-navigation operations, they tend to do so quietly,” he said. “I think there is some concern in the capitals of the other claimants that Manila is going too far and securitising the problem with external partners.”

However, Koh said Manila’s closer ties with Washington could be “free insurance” for other South China Sea claimants, which could benefit their own claims over the disputed waterway while continuing to hedge in the US-China rivalry.

“For these countries, they could continue with their current hedging policy because of the benefits there. They don’t have to be overly hawkish towards the target … and they don’t have to rock the boat with China,” he said.

“They don’t have to necessarily go out the same pathway as the Philippines, but they could actually draw benefits out of it.”