"The Russian Embassy in the Republic of India informs with deep sorrow that Russia's Ambassador Extraordinary and Plenipotentiary to India A. M. Kadakin has died after a brief illness in one of the central hospitals of New Delhi," the embassy said.
Kadakin served as Russian ambassador to India since October 2009, following a 1999-2004 stint at the post.
Kadakin was born in Chisinau, present-day Moldova, on July 22, 1949. He graduated from the Russian Foreign Ministry's Moscow State Institute of International Relations in 1972, after which he launched a diplomatic career at the Soviet Embassy in India.
The embassy said the late ambassador's "entire diplomatic career has been closely linked with the development of Russian-Indian relations since 1971."
"Deeply saddened at the passing away of Ambassador Alexander Kadakin. He was an admirable diplomat, a great friend of India and a fluent Hindi speaker who tirelessly contributed to stronger Indian-Russian ties," Modi wrote on Twitter.
Deeply saddened at the passing away of Ambassador Alexander Kadakin.
— Narendra Modi (@narendramodi) 26 января 2017 г.
Official spokesman of the Indian Foreign Ministry Vikas Swarup said on Twitter that India lost a "valued friend who nurtured Indian-Russian relationship for many decades as distinguished Russian diplomat."
Indian President Pranab Kumar Mukherjee also expressed his condolences, saying that Kadakin "spent long years here and was true friend of India."
"Russian diplomacy lost a high-class professional who devoted himself to promoting political interests of our country abroad. The huge personal contribution of Kadakin to strengthening of Russian-Indian friendship that became his lifework is invaluable," the statement published by the ministry read.
Kadakin was born in Chisinau, present-day Moldova, on July 22, 1949. He graduated from the Russian Foreign Ministry's Moscow State Institute of International Relations in 1972, after which he launched a diplomatic career at the Soviet Embassy in India.