Giving the Indo-Russian defence cooperation a major boost, the first ever Tri Services Joint Exercise between Indian and Russian Armed Forces called Exercise INDRA-2017 will be conducted from October 19 to 29. The Indian contingent consisting of 350 officers from the army, 80 from air force, two IL 76 aircraft and one frigate and corvette each from the navy would leave for Russia's eastern port city of Vladivostok for their annual military exercise- 'Indra' on October 17. The Chief of Integrated Defence Staff, Lieutenant General Satish Dua, said Russia was a natural partner and the focus of this exercise would be counter-terrorism. Dua added that these kinds of exercises would improve interoperability between the two forces, which would prove vital in joint military and humanitarian assistance and disaster relief operations. Military ties between the two countries date back to the Soviet era, when India entirely depended on Moscow to equip its armed forces. The United States has since taken over as India's top arms supplier.