By Emma Burrows and Milena Veselinovic CNN

MOSCOW (CNN) -- The Russian ambassador to the United Nations, Vitaly Ivanovich Churkin, died suddenly in New York on Monday, the Russian Foreign Ministry said.

He died at age 64, one day before his 65th birthday.

Churkin suffered from cardiac arrest while at the Russian Mission on East 67th Street, a law enforcement official said. He was taken to New York's Presbyterian Hospital, where he died.

The Russian Foreign Ministry said "the outstanding Russian diplomat died while he was in his current working role."

"We offer our condolences to the relatives of Vitaly Ivanovich Churkin," the ministry said.

Samantha Power, former US ambassador to the UN, said she was heartbroken by Churkin's death and credited him with trying to help Russian-US relations.

"Devastated by passing of UN ambassador Vitaly Churkin," Power tweeted. "Diplomatic maestro & deeply caring man who did all he cld to bridge US-RUS differences."

Matthew Rycroft, the British ambassador to the UN, called Churkin's deah the loss of a "diplomatic giant."

Developing story - more to come

CNN's Shimon Prokupecz, Holly Yan and Richard Roth contributed to this report.

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