Moscow is surprised at media leaks of investigations into the cause of death of Russian Ambassador to the United Nations Vitaly Churkin and urges Washington to use official channels in sharing information of this kind, the Russian Foreign Ministry said Wednesday.

MOSCOW (Sputnik) — Spokeswoman Maria Zakharova said the ministry "learned with bewilderment of leaks in the US media about the course of an investigation into the causes of the Russian ambassador's death."

"We believe that this information should be sent to Russia mainly through official channels so that the family is informed, his close ones should be the first to know the results of the examination," she said at a weekly briefing.

Churkin passed away in New York on Monday, a day shy of his 65th birthday.

Media reports of an examination into the cause of the death of Vitaly Churkin are an information attack, Zakharova said.

"Information attacks, leaks, citing sources. Specifically in order to avoid any speculation, we are appealing, including publicly, to the US with the urgent request that all information on this matter is first sent to Russia through official channels," she said.

US media reported that the Russian diplomat had died after suffering a heart attack at Russia’s UN mission in Manhattan.

New York City Medical Examiner's Office spokesperson Julie Bolcer estimated to Sputnik on Tuesday that the examination of the cause of Churkin's death could take "a few weeks."

"The coffin with the body of Vitaly Churkin will be sent to Russia on February 22. It will arrive in Moscow on a regular flight of Russian airlines, accompanied by relatives, on February 23," Zakharova added.