Philippine and US warships are set to kick off joint drills near disputed South China Sea waters next week, a Filipino military spokesman said Friday, amid escalating territorial rows between Beijing and its neighbours.

The drills will be held off the west coast of the Philippines' main island of Luzon, said Lieutenant Rommel Rodriguez, spokesman for Filipino side of the operations.

China claims most of the South China Sea -- including waters approaching its neighbours' coastlines -- and has been increasingly assertive in staking these claims.

But Rodriguez said the CARAT (Cooperation Afloat Readiness and Training) joint exercises, involving nearly 1,000 troops from both countries, were a regular annual event and he dismissed any connection to rising tensions in the region.

"All of our exercises will be conducted in our territorial waters. This has nothing to do with any dispute," he told AFP.

The Philippines has accused China of using "bullying" tactics in the sea, which lies on key shipping routes and is believed to harbour massive gas deposits, and Manila is lobbying for a UN tribunal to declare the Asian giant's territorial claims invalid.

Beijing placed an oil rig in disputed waters last month, sparking deadly anti-China riots in Vietnam, and on Friday announced that it was sending another four rigs to the sea. It was unclear whether any of them would be in contested areas.

The USS John McCain, an American destroyer, as well as the landing ship USS Ashland will join Philippine navy vessels for the exercises, which will last from June 26 until July 1, Rodriguez said.

They will include search and rescue, boarding and salvage drills as well as gunnery exercises next Saturday and Sunday, he added.

Rodriguez stressed that the exercises would take place "very far" from the Scarborough Shoal, an outcrop in the South China Sea currently guarded by Chinese government vessels, which was the scene of a tense standoff with the Philippines in 2012.

Manila, which has one of the weakest militaries in the region, has been increasingly turning to its main defence ally Washington to back it up against China.

The allies recently signed a new defence accord giving US forces greater access to Filipino bases in the former US colony.

Although the United States has taken no side in the territorial disputes, it has warned China against taking "destabilising actions" in the South China Sea.