Foreign ministry spokesperson Mao Ning said Beijing's Coast Guard "took necessary measures against the Philippine ships in accordance with domestic and international law".

"The operations were professional, restrained, reasonable and legal," she said.

Beijing's foreign ministry, Mao added, "has lodged stern representations with the Philippines and expresses its strong protest".

The Philippines said on Monday it had summoned China's envoy and flagged the possibility of expelling him following the most tense confrontations between the countries' vessels in years at flashpoint reefs in the disputed South China Sea.

Videos released by the Philippine Coast Guard showed Chinese ships blasting water cannon at Philippine boats during two separate resupply missions to fishermen at Scarborough Shoal and a tiny garrison at Second Thomas Shoal on Saturday and Sunday.

There was also a collision between Philippine and Chinese boats at Second Thomas Shoal, where a handful of Filipino troops are stationed on a grounded warship, with both countries trading blame.

"There have recently been multiple tense situations in the waters around Ren'ai Reef, the responsibility for which lies entirely with the Philippines," Mao said Monday, referring to the Second Thomas Shoal by its Chinese name.

"The root cause is that the Philippines broke its promise by refusing to tow away the illegally beached warship, attempting to carry out large-scale reinforcements and achieve permanent occupation," she said.