Russian Ambassador to Sudan Migayas Shirinskiy died Wednesday in the capital Khartoum, the Russian Foreign Ministry said in a statement.
Shirinskiy, born in 1954, was appointed to the post in 2013.
The diplomat died while swimming in the pool of his residence, according to state broadcaster Russia 24.
Shirinskiy manifested symptoms of an acute heart attack, embassy staff told the state broadcaster.
Embassy spokesman Sergei Konyashin said the staff called an ambulance but doctors were not able to save the ambassador.
The Sudanese police have ruled out the possibility of an assassination attempt, Russia 24 reported, quoting local law enforcement agencies.
Shirinskiy graduated from the Moscow State Institute of International Relations (MGIMO) and held diplomatic positions at Russia’s embassies in Yemen, Egypt and Saudi Arabia.
He also served as Russian ambassador to Rwanda prior to his most recent post.