The United States believes that the joint air patrols of the Russian and Chinese air forces in the Asia-Pacific region show the depth of mutual understanding of the two countries, a senior US administration official said.

US thinks this shows that China is still willing to work closely with Russia, including through military cooperation, the official said, adding that such actions should be planned well in advance.

China is not moving away from Russia. Instead, the exercise shows that China is ready to help Russia defend the east while Russia fights in its west, the source said, according to Reuters.

A senior administration official added that bomber exercises have shown that Russia will support China in its territorial disputes with neighbors in the East and South China Seas.