• China's largest coastguard ship dropped anchor in Manila's exclusive economic zone earlier this week.

• The vessel anchored there as "an intimidation," the Philippine Coast Guard said.

• Maritime relations between China and the Philippines have become increasingly tense in recent months.

The world's largest coastguard ship dropped anchor in Manila's exclusive economic zone (EEZ) in the South China Sea earlier this week, the Philippine Coast Guard (PCG) said.

Jay Tarriela, a spokesperson for the PCG, wrote on X that the authority had successfully tracked the movements of the China Coast Guard's (CCG) "165-meter monster ship" by "using Canada's Dark Vessel Detection technology."

"On July 1st, the ship departed from Hainan and entered the Philippines' Exclusive Economic Zone (EEZ) on the following day," he wrote.

The 12,000-ton CCG 5901 was later "radio challenged" by the PCG, which asked it to confirm its intentions and to remind it that it was operating within the EEZ, he added.

An exclusive economic zone is an area of the ocean "beyond a nation's territorial sea, within which a coastal nation has jurisdiction over both living and nonliving resources."

Tarriela wrote on Friday that the Chinese ship had been anchored at Escoda Shoal "for over two consecutive days" while "maintaining a close proximity" to a PCG vessel. He added that the distance between the ships was "less than 800 yards."

Tarriela later told a news forum that the Chinese vessel's moves were "an intimidation on the part of the China Coast Guard."

"We're not going to pull out and we're not going to be intimidated," he added.

Maritime run-ins between China and the Philippines are on the rise

China and the Philippines have had frequent confrontations around the Second Thomas Shoal, an atoll located within the exclusive economic zone.

China claims sovereignty over the reef and most of the South China Sea, but an international tribunal ruled in 2016 that China's claims to waters within its "nine-dash line" had no legal basis.

The Philippines grounded a ship, the BRP Sierra Madre, on the reef in 1999 to state its own claims over the area.

But the Shoal remains what the Brussels-based think tank the International Crisis Group (ICG) has called a "dangerous flashpoint," as Chinese boats continually try to prevent efforts to resupply the grounded ship.

Earlier this month, the China Coast Guard blocked a resupply mission using "dangerous and deliberate use of water cannons, ramming, and blocking maneuvers," according to a statement provided to US Naval Institute News by a spokesperson for the Office of the Secretary of Defense.

Officials from China and the Philippines met on Tuesday and said they aimed to "rebuild confidence" to help manage maritime disputes.

But the Philippines' Department of Foreign Affairs stressed that it would be "relentless in protecting its interests and upholding its sovereignty, sovereign rights, and jurisdiction" in the South China Sea.

The ICG noted in May that "relations between the two countries in the maritime domain have never been as volatile as during the last seven months."