Russia maintains positive relations with other countries of SCO, EAEU, and BRICS, especially with neighbouring Belarus, which is in the Union State, a supranational confederation of the latter with Russia. Serbia has been a historically close ally of Russia since centuries, as both countries share a strong mutual cultural, ethnic, and religious affinity. In the 21st century, Sino-Russian relations have significantly strengthened bilaterally and economically; due to shared political interests. India is the largest customer of Russian military equipment, and the two countries share a historically strong strategic and diplomatic relationship since the Soviet period.