Philippine President Ferdinand Marcos Jr. said he’s “horrified” to learn of an agreement between his predecessor, Rodrigo Duterte, and China that bars Manila from shipping construction materials to a military outpost in a disputed shoal in the South China Sea.

“If that agreement says we need to seek permission from another country to be able to do something within our own territory, it would probably be difficult to honor that agreement,” Marcos told reporters on Wednesday. “I am horrified by the idea that we have compromised through a secret agreement the territory, the sovereignty and the sovereign rights of the Philippines,” he added.

Duterte’s former spokesperson, Harry Roque, has said the Philippines entered into a “gentleman’s agreement” with China during Duterte’s term that restricts Manila from sending repair materials to a World War-II era ship that’s been serving as the nation’s outpost in the Second Thomas Shoal for about a quarter of a century.

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Philippine military missions that rotate and resupply troops on the ship, known as BRP Sierra Madre, have become a constant source of tension between Manila and Beijing, with Chinese vessels deploying water cannons on Philippine ships on several instances.

Marcos said his government isn’t aware of any record of the agreement and that they were not briefed about it when he came into office in 2022. The administration is talking to former officials during Duterte’s term about the matter, but Marcos said “we still haven’t gotten a straight answer.”

Tensions with China will be at the center of the White House summit on Thursday between President Joe Biden, Japanese Prime Minister Fumio Kishida and Marcos as Washington seeks to boost cooperation among allies in the Indo-Pacific region in a bid to counter China as Beijing presses claims over Taiwan and the East and South China Seas.

There is likely to be an agreement among the three countries “in terms of maintaining security and freedom of navigation in the South China Sea,” Marcos said. The Philippine leader will also have bilateral talks with Biden on the sidelines of the summit to continue discussions on strengthening further the alliance between Manila and Washington, he said.

Philippine protesters trample on Xi effigy, condemn China's maritime 'aggression'

Filipino protesters hold a protest outside of Chinese Consulate in Makati, Philippines

 Protesters in Manila trampled on an effigy of Chinese President Xi Jinping on Tuesday as they condemned China's "aggression" against the Philippines in the South China Sea.

The protesters marched towards the Chinese consulate in Manila, chanting "China leave!" while others called out China's "aggression" against Filipino people in the South China Sea.

The Philippines and China have had a series of maritime run-ins, including an incident last month where China used water cannon to disrupt a Philippine supply mission to soldiers stationed on a grounded warship in the disputed Second Thomas Shoal.

"Our message is addressed to the Chinese government: move out of the West Philippine Sea, dismantle its illegal structures ... recognise the 2016 arbitral tribunal ruling, and stop the harassment of Filipino fisher folk and ... Philippine supply missions," said Mong Palatino, one of the protest leaders.

China claims almost the entire South China Sea as its territory, policed by an armada of coastguard vessels, some more than 1,000 km (620 miles) away from its mainland.

A 2016 ruling by the Permanent Court of Arbitration concluded that Beijing's claim to almost the entire South China Sea was groundless, but China rejects that ruling.