China's air force has sent bombers and fighter jets on "combat patrols" near the disputed Spratly Islands and the flash point Scarborough Shoal in the South China Sea, the latest in a series of stepped-up military moves that Beijing has said will become a "regular practice."

The official Xinhua News Agency quoted military spokesman Shen Jinke as saying Saturday that the air force had sent aircraft, including several H-6K bombers, Su-30 fighters, early warning aircraft, reconnaissance planes and planes that can refuel in flight to airspace in the area.

"The flight is part of actual combat training to improve the air force's response to security threats," Shen was quoted as saying.