Stop Chinese incursion and recall your boats in the West Philippine Sea (WPS).

This was the bold reaction of Defense Secretary Delfin Lorenzana on Sunday night, March 22, after learning about verified reports that around 220 Chinese vessels manned by maritime militia were monitored at the Julian Felipe Reef (Union Reef) in West Philippine Sea.

Lorenzana said that the Department of National Defense (DND) views "with grave concern" the presence of Chinese vessels in the Philippine territory which "is a clear provocative action of militarizing the area."

"We call on the Chinese to stop this incursion and immediately recall these boats violating our maritime rights and encroaching into our sovereign territory. We are committed to uphold our sovereign rights over the WPS," Lorenzana said in a strongly-worded statement.

The Defense Chief insisted that Julian Felipe Reef is a territory located within the Philippine exclusive economic zone (EEZ) and Continental Shelf (CS) "where Filipinos have the sole right to resources under international law and the 2016 arbitral ruling."

The sighting of Chinese vessels at the Julian Felipe Reef was revealed by the National Task Force on the West Philippine Sea (NTF-WPS) on Saturday after it received confirmation from the Philippine Coast Guard.

The Julian Felipe Reef is a large boomerang-shaped, shallow coral reef at the northeast of Pagkakaisa Banks and Reefs (Union Reefs) located approximately 175 nautical miles west of Bataraza, Palawan. 

The NTF said that the reef is positioned within the country's Exclusive Economic Zone (EEZ) and Continental Shelf (CS), over which the country enjoys the exclusive right to exploit or conserve any resources which encompass both living resources, such as fish, and non-living resources such as oil and natural gas.

Lorenzana said the DND has coordinated with the Philippine Coast Guard, the National Task Force for the West Philippine Sea and the Department of Foreign Affairs "for appropriate action in the context of protecting the welfare of our Filipino fishermen, our marine resources, and maintaining peace and stability in the West Philippine Sea."

Both China and the Philippines have overlapping claims in the South China Sea. Beijing has since tightened its grip on the territories it claims in the South China Sea, including the West Philippine Sea or the area within the Philippines' 200-nautical mile exclusive economic zone.

In 2016, the Permanent Court of Arbitration ruled in favor of the Philippines' claims and invalidated the legality of China's nine-dash line claim. However, China did not honor the ruling.

Aside from China and the Philippines, other countries with overlapping claims in the South China Sea include Brunei, Taiwan, Indonesia, Malaysia, and Vietnam.