China has accused the US of flexing its military muscles in the South China Sea by conducting joint drills with two US aircraft carriers, AP reported.

Foreign ministry spokesperson Zhao Lijian told a briefing the dills were performed "totally out of ulterior motives" and undermined stability in the area.

"Against such a backdrop, the U.S. deliberately dispatched massive forces to conduct large-scale military exercises in the relevant waters of the South China Sea to flex its military muscle," Zhao noted.

The US Navy said over a weekend that at the USS Nimitz and the USS Ronald Reagan along with their accompanying vessels and aircraft conducted drills "designed to maximize air defense capabilities, and extend the reach of long-range precision maritime strikes from carrier-based aircraft in a rapidly evolving area of operations."