The Philippine military has condemned a Chinese coast guard ship's “excessive and offensive” use of a water cannon against a Filipino supply boat to block it from delivering new troops, food, water and fuel to a Philippine-occupied shoal in the disputed South China Sea. The tense confrontation on Saturday at the Second Thomas Shoal was the latest flare-up in the long-seething territorial conflicts involving China, the Philippines, Vietnam, Malaysia, Taiwan and Brunei. The disputes in the South China Sea, one of the world’s busiest waterways, have long been regarded as an Asian flashpoint and a delicate fault line in the rivalry between the United States and China in the region.