Russia and China have commenced the active phase of their joint eight-day naval drills in the disputed South China Sea amid tensions with the US, which is expanding its military presence in the region.
The active phase of “the Joint Sea 2016” started at an undisclosed location in the contested sea on Friday, after vessels departed from China’s southeastern province of Guangdong on Monday, when maneuvers were formally kicked off.
With the participation of 21 aircraft and 18 ships from both sides, including destroyers, cruisers, frigates, amphibious warfare ships and supply vessels, Russian and Chinese naval troops practiced a number of scenarios, such as emergency, search and rescue missions, as well as escorting vessels.
Chinese and Russian marines hug during “the Joint Sea 2016” naval drills in Zhanjiang, south China's Guangdong province, on September 14, 2016. (Photos by Xinhua)
The Russian Navy deployed three surface combatants and two supply ships, two choppers, 96 marines and a number of amphibious armored units.
The maneuvers have been described as “the largest operation ever” conducted jointly by the two countries. 
The joint Chinese-Russian military exercises are the fifth of their kind since 2012 and the first such drills to be held in the South China Sea. They also coincide with the commencement of the US-led “Valiant Shield 2016” drills in the West Asian Pacific.
The South China Sea is the subject of a territorial dispute between China and several regional countries.
In July, a Hague-based court of arbitration ruled that China’s claim of sovereignty over the disputed areas in the sea or its resources had no legal basis. The case was filed by the Philippines, whose economic and sovereign rights, the court said, had been violated by Beijing.
China has dismissed the ruling, saying it does not recognize the tribunal’s arbitration in the dispute.
The presence of the US in the region has upset regional powers China and Russia, which say such extra-regional presence serves to inflame tensions among countries.