MANILA: The Philippines' foreign ministry said on Tuesday it has summoned China's ambassador to Manila to protest "back-to-back harassments" in the South China Sea at the weekend, as longstanding geopolitical tensions continue in the strategic waterway.

Manila has asked China to direct its vessels to cease and desist from what it said were illegal actions and dangerous manoeuvres against Philippine vessels, and stop interfering in legitimate Philippine activities, the ministry said in a statement.

Foreign Affairs Undersecretary Ma. Theresa Lazaro verbally delivered the protest against the Chinese manoeuvres that led to a collision, and against use of water cannons against Philippine vessels sending supplies to troops stationed in an ageing warship at the Second Thomas Shoal.

"The actions of the Chinese vessels within the Philippine exclusive economic zone are illegal and violate the freedom of navigation," the ministry said.

It also protested China's use of water cannons against three fisheries bureau vessels on their way to send oil and groceries to fishermen near the Scarborough shoal.

The Chinese embassy in Manila did not immediately respond to request for comment.

The two neighbours traded accusations on Sunday, and the Philippines called China's actions a "serious escalation".

China's foreign ministry protested over what it said was a collision on Sunday, but the Philippines said Chinese coastguard and maritime militia repeatedly fired water cannons at its resupply boats, causing "serious engine damage" to one, and "deliberately" ramming another.

The United States, the Philippines' treaty ally, and the United Kingdom, both expressed support for the Philippines and condemned the actions of China, which claims sovereignty over almost the entire South China Sea, a conduit for more than $3 trillion of annual ship-borne commerce.

The Philippines, Vietnam, Indonesia, Malaysia and Brunei, have competing claims. The Permanent Court of Arbitration in 2016 said China's claims had no legal basis.