MANILA The Philippine Coast Guard (PCG) is committed to sustaining a presence in a disputed area of the South China Sea to ensure China does not carry out reclamation activities at the Sabina Shoal, its spokesperson said on Monday.

The coast guard said on Saturday that it had deployed a ship to Sabina Shoal, where it accused China of building an artificial island, amid an escalating maritime row, adding that two other vessels were in rotational deployment in the area.

Since the ship's deployment in mid April, the coast guard said it had discovered piles of dead and crushed coral that had been dumped on the sandbars of Sabina Shoal, altering their sizes and elevation.

PCG spokesperson Jay Tarriela told a press conference on Monday that the Coast Guard had to make sure it was able to prevent "China from carrying out a successful reclamation in Sabina Shoal".

He said the coast guard was committed to maintaining a presence at the shoal, which Manila calls Escoda.

Located within the Philippines' exclusive economic zone, the shoal is the rendezvous point for vessels carrying out resupply missions to Filipino troops stationed on a grounded warship at the Second Thomas Shoal, where Manila and China have had frequent maritime run-ins.

China has carried out extensive land reclamation on some islands in the South China Sea, building air force and other military facilities, causing concern in Washington and around the region.

Tarriela believed the coast guard had been effective in deterring China from doing small-scale reclamation. It had not documented any activity from the Chinese vessels present in Sabina Shoal since it deployed its multi-role response vessel there in mid April.

"China does not want to get caught," Tarriela said.

There was no immediate comment from the Chinese Embassy in Manila on Tarriela's remarks.

"China has indisputable sovereignty over the South China Sea Islands and the adjacent waters," it said in a statement on Sunday.

China claims almost all of the vital waterway, including parts claimed by the Philippines, Brunei, Malaysia, Taiwan and Vietnam. The Permanent Court of Arbitration ruled in 2016 that Beijing's claims had no basis under international law, a decision that China rejects.

  - Reuters