The United States has expressed concern over the presence of Chinese militia in the West Philippine Sea, which State Secretary Antony Blinken described as a "direct threat" to the people and to the environment.

During his visit to the Philippines on Saturday, Blinken urged all concerned parties to "continue to bring focus to this issue of particular concern."

He made the call as Department of Foreign Affairs (DFA) Secretary Enrique Manalo bared that the Philippines is concerned about some Chinese vessels that have been conducting illegal and unregulated fishing activities in the waters where the Philippines has "legitimate sovereign rights."

"We see it much more broadly in South China Sea and beyond, and it's a direct threat to the livelihoods of tens of thousands of people engaged in fishing to support themselves and their families," Blinken told reporters in a virtual press conference.

"It's also a threat because it threatens the fish stock, it threatens the environment in the way it's done," he added.

According to Manalo, the Philippines already filed diplomatic protests against China regarding the matter.

Although the US has no direct involvement in the issue, Manalo expressed openness to discuss it with the US in the context of bilateral relations.

"Now this is an area at the same time where we can have an ongoing discussion," Manalo said, "but at the same time we continue to have bilateral negotiations or discussions even with China within the framework of our existing dialogue mechanism."