Lawmakers had asked him on Wednesday in the Senate whether China would attack Taiwan and he told them it was very unlikely. “In the unlikely event China will attack, we just watch,” he said.

In light of these tensions, Manila had called for a review of its Mutual Defence Treaty (MDT) with Washington.

“We believe it is time to sit down with our US counterparts and revisit the terms of our alliance. We are partners. We have deep historical ties. We must clearly define our roles and responsibilities when the need arises to be joined in arms,” Lorenzana said.

He disclosed that one of the areas he wanted clarified was what would trigger mutual responses of aid. For instance, he asked whether the Philippines had to get involved if a shooting war broke out between China and the US “somewhere there in Mischief Reef”.

Mischief Reef, in the Spratly Islands, is claimed by China, the Philippines, Taiwan and Vietnam, although in recent years Beijing has staked its claim by building a large man-made island with airfield and landing strip there.

He noted that under the terms of the present MDT, the US “will only come to our aid when the metropolitan Philippines is attacked”.

On Manila’s relations with China, Lorenzana described the Duterte administration’s approach as “calibrated, comprehensive, and constructive” engagement.

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The Philippines and China had a dangerous stand-off in 2012 that lasted for months over the Scarborough Shoal in the South China Sea, which both countries claim as their own.

In 2013, Manila initiated a legal challenge against Beijing’s territorial claims at the Permanent Court of Arbitration in The Hague and the tribunal rejected Beijing’s claims in 2016, saying they lacked a legal basis. However, when President Rodrigo Duterte came to power that year, he said he would set aside the ruling for now.

The Philippines continues to view the tribunal ruling as valid and legitimate, Lorenzana said: “We have not, and we will not, surrender any part of our territory.”

While Lorenzana was speaking, Rear Admiral Xu Haihua, deputy chief of staff of China’s North Sea Fleet, was delivering a speech to mark the historic docking of the guided missile-frigate Handan and two other naval ships – Wuhu, another guided-missile frigate, and replenishment ship Dongpinghu – in Manila Bay.

Local media quoted Xu as saying that the goodwill visit showed “the new era, with strategic guidance of Presidents Xi Jinping and Duterte, opening a new chance for China-Philippine relations”.

Supreme Court Associate Justice Antonio Carpio, who spoke after Lorenzana, showed Chinese-made historical maps which he said indicated that what is now known as the Spratlys and Scarborough Shoal were never a part of ancient China.

China has been claiming historical rights over these areas.

Carpio said that the challenge for Filipinos was “how to convince the Chinese people that this historical narrative is the fake news of the century”.

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“The intent of China is very clear. They want to control the West Philippine Sea. We should always bear that in mind. Their intention from the very start is to grab 80 per cent of our EEZ [exclusive economic zone]. They may slow down for a while but they will continue to march toward that objective.”

Carpio, who is related to the husband of Duterte’s daughter, Davao City Mayor Sara Duterte-Carpio, was asked to comment on the president’s friendly approach to China but would only say: “The president is the chief architect of foreign policy.”

He suggested, though, that “we should file protests every time” Filipino fishermen were barred from fishing freely.

“There are many ways of strengthening our position. I’m not happy (with Duterte’s approach) but there’s nothing I can do about it,” Carpio said. “If we don’t file a note verbale and protest, then we waive [our sovereign rights].”