MANILA - The Philippines should file a diplomatic protest and seek joint patrols with other countries to counter Beijing's recent establishment of 2 administrative units on islands in the South China Sea, a new move to show assertiveness in the disputed waters despite the global emergency over the coronavirus crisis, left-wing leaders said Tuesday.

While other claimants are preoccupied with tackling the new coronavirus pandemic, China on Saturday said it had established an administrative district on the Paracel islands, being claimed by Vietnam, and another on the Spratly Islands, where Philippine claims on the resource-rich waters are located, said Bayan Muna Party-list Rep. Carlos Isagani Zarate.

"This is totally outrageous, unacceptable and shows utter disrespect of Philippine sovereignty," said Zarate, who is also deputy minority leader of the House of Representatives.

Malacañang "should issue a diplomatic protest" as failure to do so would "only further embolden China to make a mockery of our sovereignty," he said in a statement.

The Philippines should also push for joint patrols with other claimants like Vietnam, Malaysia and Brunei "because this can become a bigger deterrent to China's plans", said Bayan Muna chairman Neri Colmenares.

"Instead of justifying the Chinese' aggressive action, the government should also rally the international community in condemning and countering these latest Chinese actions," he said.

"Like a thief in the night, China is exploiting the COVID crisis to trample on our sovereign rights in the WPS (West Philippine Sea)," he added, referring to the country's exclusive economic zone in the South China Sea.

Acting on a Philippine plea, a United Nations-backed court in 2016 junked Beijing's "historic rights" to nearly 90 percent of the resource-rich waterway. However, the tribunal has no enforcement mechanism and China has refused to recognize the ruling.

A Chinese government survey ship was spotted last week tagging an exploration vessel operated by Malaysia’s state oil company Petronas, months after it undertook a similar patrol off Vietnam.

The incident prompted the United States to call on China to stop its “bullying behavior” in the disputed waters, citing concern over Beijing's provocative actions towards offshore oil and gas developments there.

- With a report from Reuters