A senior Russian diplomat was found dead in his Athens apartment on Monday, a Greek police official said.
Andrey Malanin, 54, was head of the consular section, according to the embassy's website.
He was found on the floor of his bedroom by a member of the embassy's staff with no evidence of a break-in, the official said on condition of anonymity.
"At first sight, we are talking about natural causes," the police official said, noting that police were investigating and authorities were awaiting the coroner's report.
Russia's ambassador to Turkey, Andrei Karlov , was assassinated last month while speaking at a photo exhibit.
President Putin was among mourners, including relatives and fellow diplomats laying flowers near Karlov's body in a ceremony in the marbled lobby of the looming Stalin-era skyscraper in central Moscow.