Senate President Juan Miguel "Migz" Zubiri said on Saturday, May 18, that China's reported move to allow its Coast Guard to detain those who will illegally enter ​the waters under its jurisdiction was an "illegal act" in violation of the United Nations Convention on the Law of the Sea (UNCLOS).

In an interview on DWIZ radio, Zubiri said that under the UNCLOS, there should be freedom of navigation in the areas of the West Philippine Sea (WPS).

"Ibig sabihin, kahit sino po, mangingisda man, cargo ship, makakadaan diyan na hindi mababahala, hindi madadakip at mahuhuli nitong mga claimant countries. (This means, anyone, whether a fisherman or a cargo ship can go through there without the fear of being apprehended by claimant countries). That is under UNCLOS. There should be freedom of navigation and a free and open access in the Indo-Pacific region," he said.

"Kapag ginawa nila yan that's a unilateral move na illegal po yan under the UNCLOS at yung China nakapirma diyan, member ng convention na yan (If they do that, that's considered a unilateral move that is illegal under the UNCLOS and China is part of that convention)," he added.

China has​ reportedly ​allowed its Coast Guard to detain starting in mid-June those who will illegally enter ​the waters under its jurisdiction for up to 60 days without trial​ following the issuance of new regulations for its maritime troops.

This was according to a report from the South China Morning Post.

It also said that Beijing on Wednesday rolled out a new set of regulations for its Coast Guard ​when it released a 92-page document titled “Procedural Regulations on Administrative Law Enforcement of Coast Guard Agencies".

Its release coincided with the mission of civilian group Atin Ito on Wednesday to sail towards Bajo de Masinloc or the Scarborough Shoal, a feature in the WPS that China claims to be its own.

"Talagang illegal act yan at magdadagdag ng tensyon sa region (It's really an illegal act and can inrease tension in the region)," Zubiri said.

"'Pag ginawa po yan nakakatakot. Kasi siyempre dedepensahan natin ang ating mga kababayan, dedepensahan natin ang ating mga sarili at baka lalong maging mainit ang tensyon dito sa WPS (If they do this it's alarming. Because we will have to defend our people and ourselves, and the tension here in WPS might intensify)," he added.

Zubiri also mentioned the possibility that this act may trigger the Mutual Defense Treaty (MDT).

United States (US) President Joe Biden mentioned in April that any attack on Philippine aircraft, vessels, or its military in the South China Sea would invoke the MDT.

Regarding the move, the Chinese Embassy in Manila has also released a copy of the order. As of this writing, Philippine reporters are still waiting for its English translation.

Meanwhile, Senator Jinggoy Estrada said in a statement that he was awaiting the pronouncement of the Department of Foreign Affairs (DFA) if they have received any official document on the issue.

"Nonetheless, we have taken note of this matter. While we respect China’s right to safeguard its territorial interests, we also emphasize the importance of adhering to international norms and agreements," he said.

"The Philippines remains committed to upholding our rights and interests in the [WPS]. We hope China will likewise respect the rights of other nations operating in these waters. We encourage all parties to exercise restraint and seek peaceful solutions to disputes," he added.