President Ferdinand Marcos Jr. on Wednesday slammed China's recently announced policy of detaining foreign fisherfolks entering disputed areas in the South China Sea.

In a briefing with the Philippine media delegation in Brunei, Marcos expressed particular concern over China's new policy of threatening to detain Filipino fishermen entering the disputed waters.

China, which is involved in maritime sovereignty disputes with the Philippines and other claimant nations, has implemented new rules starting 15 June. These rules enforce a 2021 coast guard law, allowing the detention of foreigners suspected of trespassing.

"The new policy of threatening to detain our own citizens, that is different," Marcos said.

"That is an escalation of the situation. So, yes, this is now very worrisome," he added.

Marcos also criticized China's unilateral imposition of a four-month fishing ban in the South China Sea, including parts of the disputed West Philippine Sea, calling it an extension of their "expansive claims."

The Chief Executive acknowledged the practice of seasonal fishing bans, but emphasized the lack of prior agreement with China on this specific measure.

"It's just an extension, again, of their claim that this is all the maritime territory of China. It's nothing new," Marcos stated, highlighting the longstanding territorial dispute.

"Sometimes there are fishing bans because it's the season, and this is something that we have not really agreed upon before," he added.

The Philippines has long contested China's expansive claims in the South China Sea, which includes the resource-rich West Philippine Sea. Filipino fishermen have reported harassment from Chinese vessels in these contested waters, hindering their livelihood.

Beijing asserts jurisdiction over the majority of the South China Sea, a crucial waterway for over $3 trillion in annual maritime trade.

In 2016, an international arbitral tribunal ruled that China’s extensive claims lacked any basis under international law, a decision that Beijing has rejected.

China maintains that historical records and old maps clearly establish its sovereignty over most of the sea and many of its islands.