Cambodia and China have kicked off their annual military exercises as concerns grow in the US about Beijing's increasing influence in the Southeast Asian nation.

Cambodian military officials say this year's "Golden Dragon" drills got underway on May 16 in the country's Kampong Chhnang and Preah Sihanouk provinces.

More than 1,300 personnel from Cambodia and 700 from China are taking part in the exercises, which run through May 30. 14 warships will be deployed along with helicopters and other advanced weapons.

At Thursday's opening ceremony, China showcased its robotic dogs equipped with machine guns.

Officials say the annual drills are focused on boosting counter terrorism operations and humanitarian relief missions.

Meanwhile, two Chinese warships have been docked since last December at Cambodia's Ream Naval Base near the South China Sea.

The US and its allies have been increasingly concerned that the base could become a new strategic outpost for the Chinese navy as the two countries strengthen their military cooperation.