Photo taken on Dec. 4, 2017 shows an aircraft of the Chinese air force taking off for a drill at an airport in China. The Chinese air force said Monday that its surveillance aircraft had recently conducted high-sea drills in the Yellow Sea and East China Sea to improve combat readiness and safeguard the country's "strategic interests." (Xinhua/Zhang Lei)

BEIJING, Dec. 4 (Xinhua) -- The Chinese air force said Monday that its surveillance aircraft had recently conducted high-sea drills in the Yellow Sea and East China Sea to improve combat readiness and safeguard the country's "strategic interests."

The aircraft took an air route that was not previously flown to areas where they had never been, said Shen Jinke, spokesman for the Chinese People's Liberation Army(PLA) Air Force.

The air force's fighter jets, airborne early warning aircraft and surface-to-air guided missile forces coordinated with surveillance for the training, Shen said.

The Chinese air force will conduct high-sea exercises under combat conditions on a regular basis, the spokesman said.