PRESIDENT Ferdinand R. Marcos, Jr. on Wednesday said the presence of Chinese warships in the South China Sea and increased cyberattacks are worrisome, but these would not deter his resolve to defend Philippine sea claims and protect Filipino fishermen.

“Before, only the Coast Guard of China was moving in our areas,” he told reporters before flying to Australia for a state visit. “Now, it’s the Navy too.”

The Philippine Coast Guard spotted Chinese Navy vessels during a patrol mission by a fishery bureau vessel near Scarborough Shoal last week, just as Manila raised alarm over increased cyber-attacks and electronic interference targeting its communication equipment.

Mr. Marcos, who has pursued closer security ties with the US and other western allies, said his government would continue to defend Filipino fishermen’s access to Scarborough Shoal, which Manila calls Bajo de Masinloc.

“The basic principle there is that the fishers must be allowed to fish in their traditional fishing grounds, which belong to the maritime territory of the Philippines,” he added.

Meanwhile, the US Indo-Pacific strategy is unlikely to change if Donald Trump wins the presidential race, Philippine Ambassador to the US Jose Manuel G. Romualdez said.

In a speech, the Philippine envoy said he was in touch with one of Mr. Trump’s close advisers, who told him about the continuation of the US stance in the region.

The Philippines would not let up in asserting its sea claims, Mr. Romualdez said in a speech, as tensions in the South China Sea continue to simmer, with China vehemently opposed to what it considers incursions by Philippine vessels into what it considers its waters.

The “aggression” we are now facing is very real, Mr. Romualdez said, adding that the Philippines hopes China would see the value of continuing economic activity between them while trying to peacefully resolve their issues.

In an interview with Reuters last week, Mr. Romualdez, a cousin of President Marcos, said the Philippines was closely watching the US presidential race but would view any change in leadership as an opportunity to renew the strengthening alliance between the two countries.

Their security engagements have stepped up considerably under US President Joseph R. Biden and Mr. Marcos, with both leaders keen to counter what they see as China’s aggressive actions in the South China Sea and near Taiwan.

Mr. Biden is likely to face Mr. Trump, the Republican frontrunner to become the party’s presidential candidate, in a rematch in November’s presidential election.

Under Mr. Marcos, the Philippines has nearly doubled the number of its bases accessible to US forces. Mr. Marcos last year succeeded in pushing Washington to clarify the extent of a 1951 Mutual Defense Treaty that binds them to defend each other in case of an attack.

Mr. Romualdez on Wednesday said it was possible there could be one major “accident” in the South China Sea that could lead to that treaty being invoked, but hoped that would never happen.

A United Nations court based in the Hague in 2016 voided China’s claim to more than 80% of the South China Sea and upheld the traditional fishing rights of small-scale Filipino and Chinese fishermen at Scarborough Shoal.

The shoal is 240 kilometers west of the main Philippine island of Luzon and is nearly 900 kilometers from Hainan, the nearest major Chinese landmass.

The Philippine Navy on Tuesday said it had monitored increased cyberattacks and electronic interference targeting their communication capabilities.

These usually happened during resupply missions, said Roy Vincent Trinidad, the Navy’s spokesman for South China Sea issues. But the Navy could not determine the source of the interference.

It made the report after Philippine Coast Guard (PCG) spokesman Jay Tristan Tarriela accused China at the weekend of preventing Philippine vessels from broadcasting their positions at sea by jamming the signal of their tracking system.

“We assume that they do the jamming every time they release their statements that they repelled our vessels.”

The PCG last week belied the Chinese coast guard’s claim it had driven away a Philippine fishery vessel from waters near Scarborough Shoal, which China has occupied since 2012.

Also on Wednesday, Mandaluyong City Rep. Neptali Medina Gonzales II, who heads a House of Representatives special committee on the West Philippine Sea, said the government would continue filing diplomatic protests against China to assert its claim in the South China Sea.

“We have to show to the world that we are not relinquishing our claim,” he said in a statement. “We cannot be silent on the issue as the countries who are supportive of our cause will also lose interest if we ourselves cannot show any interest,” he added in mixed English and Filipino. — Kyle Aristophere T. Atienza and Kenneth Christiane L. Basilio with Reuters