MANILA — Former Senate president Juan Ponce Enrile on Monday asked why Manila's ally United States failed to stop China from seizing Scarborough Shoal in the West Philippine Sea nearly a decade ago.

In a taped meeting with President Rodrigo Duterte, Enrile said still does not know who sought the help of the United States in 2012 to end a standoff between the Philippines and China.

The standoff erupted after a Philippine Navy ship attempted to arrest Chinese fishers.

Following a deal that the US forged, the Philippines under the administration of then President Benigno Aquino III pulled back its ships from the area.

However China "deceitfully" the agreement, retained its ships at Scarborough, and continues to occupy the area, former Foreign Affairs secretary Albert del Rosario had said.

• Duterte told about China's control of Scarborough Shoal; Beijing breached pull-out deal

Enrile questioned why the US failed to reprimand China for breaking the deal.

"Ang impression ko ba ay parang ginamit lang tayo sa bagay na iyon. Ano mang interes ang nauukol para sa Amerika, hindi ko alam," he said. "Hanggang ngayon hindi ko masagot kung bakit yung mediator natin ay hindi tayo tinulungan para tumupad naman ang Tsina sa kasunduan na umatras sila."

(My impression is that we were used in that issue. Whatever interest America has, I don't know. Until now, I cannot answer why out mediator did not help us press China to fulfill the deal from which it backed out.)

The United States has stressed it is neutral in the long-running maritime dispute, despite offering to help boost the Philippines’ decrepit military forces. China has warned that "external forces" should not get involved.

• US bolsters presence in South China Sea with amphibious assault ship
• US waiting for Philippines to call for help vs Chinese sea incursion: Manila envoy

JPE DRAGS TRILLANES INTO ISSUE

Enrile also brought up Aquino's go signal for then senator Antonio Trillanes IV to hold backdoor negotiations with Chinese officials during the 2012 standoff. Enrile said Trillanes bypassed Philippine Ambassador to China Sonia Brady.

• Ambassador Brady's notes on Trillanes' China activities

"Sinabi ko kay Mr. President, dahan-dahan medyo masalimuot ata ‘yan sapagkat hindi natin alam kung anong mga pinag-usapan nila ni Trillanes doon sa mga kinakausap niya sa Tsina," said Enrile.

(I told Mr. President to be careful. It might be a sensitive issue because we do not know what Trillanes said to those he talked with in China.)

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Trillanes is a vocal critic of Duterte. The former lawmaker said last week he was eyeing the presidency in 2022.

On Saturday, he said Duterte keeps on reviving the Scarborough Shoal issue to divert the attention of the public.

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In March, Trillanes said that after his negotiations with China for three months over the standoff at the Scarborough Shoal, the number of Chinese ships in the area reduced from "80-100, to just three, all of which were positioned outside the shoal."

Trillanes said he was designated by President Benigno Aquino III in May 2012 as backchannel negotiator at the height of the standoff, and "the issue of sovereignty WAS NOT COVERED and WAS NEVER DISCUSSED."

"I WAS ABLE TO ACCOMPLISH MY MISSION. Looking back, I can proudly say that this is probably THE BIGGEST ACHIEVEMENT in my career as a public servant. An invasion or an armed conflict with a regional power was averted through those backchannel talks," Trillanes said on his Facebook account.

Scarborough Shoal, located 124 nautical miles west of Zambales, is one of the region's richest fishing grounds.

China's seizure of the area prompted the Aquino government to file an arbitration case against Beijing before a United Nations-backed court.

Shortly after Duterte took office in the 2016, the tribunal ruled in favor of Manila and junked Beijing's sweeping claims to the South China Sea, within which is the smaller West Philippine Sea.

But almost a decade after the standoff, Chinese vessels continue to encroach into the exclusive economic zone of the Philippines in the waterway.

• About 200 ships still moored at West Philippine Sea, geo-analyst says
• Philippines rejects Chinese fishing ban in West Philippine Sea

Duterte recently likened to a piece of "paper" the landmark arbitration award. Roque said there is no enforcement mechanism that would make Beijing follow the ruling.

• China, not Duterte, will throw away Philippines' arbitral victory, says Palace

At stake is control over what are believed to be significant reserves of oil and gas. Estimates for proven and undiscovered oil reserves in the entire sea range from 28 billion to as high as 213 billion barrels of oil, the US Energy Information Administration said in a March 2008 report.

– With a report from Reuters