MANILA, Dec 11 (Reuters) - The United States has called out China for interfering in the Philippines' maritime operations and undermining regional stability, urging Beijing to stop "its dangerous and destabilizing conduct" in the South China Sea.

The Philippines and China have traded accusations over a ramming incident at the weekend involving their vessels while Manila's vessels were on a resupply mission to Second Thomas Shoal where its soldiers are stationed in a deliberately grounded navy vessel.

"Obstructing supply lines to this longstanding outpost and interfering with lawful Philippines maritime operations undermines regional stability," State Department spokesperson Matthew Miller said in a December 10 statement shared by the U.S. embassy in Manila on Monday.

The United States has called on China to comply with a 2016 arbitral ruling that invalidated its sweeping claims in the South China Sea.

At the weekend, the Chinese coastguard called on the Philippines to stop its "provocative acts", saying China would continue to carry out "law-enforcement activities" in its waters.

The United States also reiterated its support for treaty ally, the Philippines, and reaffirmed its commitment to the mutual defence pact between the two countries.

Philippines President Ferdinand Marcos Jr. separately said the presence of Chinese coast guard vessels and maritime militia in his country's waters is illegal and their actions against Filipinos is an outright violation of international law.

The Philippines has further steeled its determination to defend and protect its nation's sovereign rights in the South China Sea amid "aggression and provocations" by China, Marcos posted on the X social media site late on Sunday.

"We remain undeterred," the president said.

Photo from Reuters