Illustration: Liu Rui/GT

There is no gray zone on the Taiwan question. The Philippine side should abide by the one-China principle with concrete actions. External interactions of China's Taiwan region should be handled in strict accordance with the one-China principle, Chinese Foreign Ministry spokesperson Mao Ning said on Thursday. 

Mao made the remarks when asked to comment on a Philippine diplomat's claim that the Philippines is exploring deeper cooperation with Taiwan to protect undersea cables and address so-called gray-zone activities, despite its one-China policy.

The Philippine diplomat's recent claims exposed the Marcos Jr. administration's ulterior motive of playing the "Taiwan card" to gain leverage in the South China Sea. Such duplicitous words and actions amount to a deceptive political ploy that will not succeed, said a Chinese expert, noting that the Philippines will ultimately reap what it sows and its moves to heighten cross-Straits tensions and persist in provocations in the South China Sea will backfire.

Felipe F. Carino III, Manila's deputy chief of mission in Washington, told a seminar on Wednesday this "pragmatic and practical approach" with Taiwan was necessary to protect mutual ⁠interests in the Bashi Channel between Taiwan region and the Philippines, according to a Reuters report.

Speaking to Washington's Center for a New American Security, Carino linked cable security to South China Sea tensions, but did not mention China by name. "We are exploring deeper cooperation with our friends in Taiwan," Carino claimed, adding that the Philippines was doing so "not withstanding our one China policy," according to the report. 

Asked if this cooperation could include joint patrols or accountability for vessels that disrupt communications, Carino said he did not have details, but said: "I'm sure that this is a constantly evolving cooperation, and some of the things that you mentioned may be actually coming to fruition," per Reuters.

The Democratic Progressive Party (DPP) authorities in the Taiwan region initially hyped the undersea cable issue, making false accusations against the Chinese mainland. Philippine diplomats are now exploiting it to stoke the "China threat" narrative, bolster their defenses and play the "Taiwan card" to secure US support, ultimately seeking leverage in the South China Sea, Zheng Jian, a professor at the Taiwan Research Institute of Xiamen University, told the Global Times on Thursday.

The Marcos Jr. administration is playing the "Taiwan card" to draw in the US, link South China Sea issue with the Taiwan question, and integrate the Philippines into the US first-island-chain defense strategy to contain China, said Zheng, noting that by paying lip services to the one-China principle while pursuing highly sensitive security cooperation with the Taiwan region, Manila seeks to conceal its intentions and evade international scrutiny. 

"But such a deceptive political ploy will not succeed," said the expert. 

According to a report from the Nikkei Asia on Monday, Taiwan region and the Philippines "are taking steps to boost maritime ties after decades of distance." A Taipei Times report on Wednesday noted that the Taiwan regional coast guard authority donated a patrol vessel to the Philippines, but it will not be used in waters near Taiwan region.

Recent interactions between the Philippines and the DPP authorities in the Taiwan region reflect political calculations on both sides. However, pursuing so-called security or even military cooperation in defiance of the one-China principle crosses red lines and will inevitably draw firm opposition and countermeasures from the Chinese mainland, experts warned.

Zheng said Manila's attempts to link South China Sea issue with Taiwan question risk drawing the Philippines into a cross-Straits conflict through its cooperation with the Taiwan region.