"Alongside our Allies and partners, we are closely tracking the military activities of the People’s Republic of China (PRC) in the South China Sea and Philippine Sea, as well as the ongoing Russia-China exercise in the East China Sea," the US military said in a statement.
Washington continues operations in the region "to maintain peace and stability; uphold international law, including freedom of navigation and overflight; and support unimpeded commerce and other lawful uses of the sea," the statement added.
In this photo released by China's Xinhua News Agency, officers and soldiers of China's People's Liberation Army (PLA) Navy hold a welcome ceremony as a Russian naval ship arrives in port in Zhanjiang in southern China's Guangdong Province, Monday, Sept. 12, 2016
© AP Photo / Zha Chunming/Xinhua
"We continue to oppose any military pressure or coercion against our Allies and partners in the region. The United States has been very clear: we will continue to be forthright in opposing any behavior that challenges and bends the rules which the international community has relied upon to maintain stability and peace," the statement read.
Earlier this week, the Russian Defense Ministry said that a detachment of ships from Russia's Pacific Fleet had sailed toward the East China Sea to participate in Russian-Chinese naval drills from December 21-27.