Russia's ambassador to Sudan has died at his residence in Khartoum, Sudanese and Russian officials have said.
Mirgayas Shirinsky, a career diplomat who was in his early 60s, was at least the sixth serving Russian diplomat to die in the past two years.
A Sudanese Foreign Ministry statement did not give the cause of death, but Russian Embassy spokesman Sergei Konyashin said there were signs Shirinsky had suffered a severe heart attack on August 23.
"Doctors were summoned but were unable to save him," Konyashin said on state-run Rossia-24 television.
A Sudanese police spokesman said it was believed that Shirinsky had high blood pressure.
The AFP news agency quoted a senior police officer in Khartoum whom it did not name as saying the ambassador "died while he was swimming in his pool at his house."
Shirinsky's death came six months after the longtime Russian ambassador to the UN, Vitaly Churkin, died suddenly in New York on the day before his 65th birthday.
The New York City medical examiner's office declined to release autopsy results, citing diplomatic immunity, but The Associated Press quoted senior officials speaking on condition of anonymity as saying the examiner found that Churkin died of a heart attack.
The Russian ambassador to India, Aleksandr Kadakin, died in January in New Delhi at the age of 67. State-run Russian media reported that the cause was heart failure.
Russian and Greek officials said that consul Andrei Malanin, who was found dead on his bedroom floor in Athens earlier in January, died of natural causes. He was 55.
The Russian ambassador to Turkey, Andrei Karlov, was shot dead by an off-duty Turkish police officer at a photography exhibit in Ankara on December 19, 2016.
Andrei Vorobyov, the Russian charge d'affaires in Ukraine, died in Moscow on May 30, 2016, after suffering a stroke, according to state news agency TASS.
With reporting by AFP, TASS, RIA, Reuters, and Hurriyet