MOSCOW -- Diplomats, colleagues and relatives said their final farewells Friday to Vitaly Churkin, Russia's long-time ambassador to the United Nations who died earlier in the week.

Foreign Minister Sergey Lavrov praised Churkin as an "exceptional professional and people's diplomat" in remarks at the funeral, where the open casket was draped in a Russian flag, flanked by an honour guard and surrounded by wreaths in a memorial chapel.

"We are saying goodbye to our friend, a prominent diplomat of the modern age, a person who always reached the maximum possible results wherever the motherland would send him," Lavrov said before the burial at Troyekurovskoye Cemetery in western Moscow.

The Order of Courage, a medal awarded posthumously to Churkin by President Vladimir Putin, was displayed at the coffin.

Churkin died Monday at a New York hospital at age 64. Medical examiners who performed an autopsy said more tests were needed to determine the cause of death.

He had been Russia's envoy at the UN since 2006. He was the longest-serving ambassador on the Security Council, the UN's most powerful body. He also served as ambassador in Canada and Belgium, and was a spokesman for the Foreign Ministry in the early 1990s.