China accused the Philippines on Friday of having "provoked trouble" in the South China Sea with U.S. backing, which Manila denied, as tensions between the two neighbours continue.

"The Philippine side, with U.S. support and solicitation, has been stirring up trouble in many spots in the South China Sea," Wu Qian, a spokesperson for China's defence ministry, said on its official WeChat account.

"The Philippines is well aware that the scope of its territory is determined by a series of international treaties and has never included China's" Spratly Islands and Scarborough Shoal, he added.

The Philippines denied China's claims.

"Such statements coming from the Ministry of Defense are clear evidence of bullying," Jay Tarriela, Philippine Coast Guard spokesperson for the South China Sea, posted on social media platform X on Saturday.

China, which aims to intimidate the Philippine government into withdrawing its support for its own fishermen, is "escalating its rhetoric by instructing its defense ministry to issue warnings about using stronger countermeasures," he added.

Beijing and Manila have been involved this year in a series of confrontations at reefs and outcrops in the South China Sea, which China claims almost in its entirety.

The Philippines, Brunei, Malaysia, Taiwan and Vietnam also claim parts of the sea. They are concerned China's expansive claim encroaches into their exclusive economic zones (EEZ), non-territorial waters that extend 200 nautical miles (370 km) from the coasts of a nation's land.

The U.S. Navy's 7th Fleet, the largest of the U.S. Navy's forward-deployed fleets that operates in the Indo-Pacific, did not immediately respond to a request for comment.

Philippines officials said last week that Chinese coast guard vessels had fired water cannon and side-swiped a Manila fisheries bureau boat on the way to deliver supplies to Filipino fishermen around the Scarborough Shoal, a move that drew condemnation from the U.S.

China's Coast Guard said that four Philippine ships had attempted to enter waters it described as its own around the Scarborough Shoal, which Beijing calls Huangyan Island.

China submitted nautical charts earlier this month to the United Nations that it said supported its claims to the waters, which a 2016 international tribunal found to be a long-established fishing ground for fishermen of many nationalities.

Following the charts' submission, a spokesperson for the Philippines' National Maritime Council said China's claims were baseless and illegal.

The 2016 tribunal ruled that China's claim had no basis under the U.N. Convention on the Law of the Sea (UNCLOS), and that its blockade around the Scarborough Shoal was in breach of international law.

Beijing has never recognised the decision.

Sovereignty over the Scarborough Shoal has never been established.

The Philippines and other members of the Association of Southeast Asian Nations have spent years negotiating a code of conduct with Beijing for the strategic waterway, with some nations in the bloc insisting that it be based on UNCLOS.

EEZs give the coastal nation jurisidiction over living and non-living resources in the water and on the ocean floor. (Reporting by Joe Cash in Beijing and Neil Jerome Morales in Manila.