TEHRAN (Press Shia) – Russia staged a somber funeral ceremony Thursday for Andrei Karlov, the Russian ambassador to Turkey who was shot dead in Ankara.

Russian President Vladimir Putin, who promised retribution after Karlov, 62, was killed Monday, was among mourners, including relatives and fellow diplomats, who gathered at the foreign ministry building where the slain envoy’s body lay in an open casket in Russian Orthodox tradition, Reuters reported on Friday. 

Russia and Turkey say the assassination was a failed attempt to derail a rapprochement between Moscow and Ankara which has seen them cooperate more closely over Syria.

Prime Minister Dmitry Medvedev and Foreign Minister Sergey Lavrov laid flowers near Karlov’s body in a ceremony in the marbled lobby of the looming Stalin-era skyscraper in central Moscow. Lavrov said Karlov had been the victim of “a despicable terrorist act.”

Putin, who has said he knew Karlov personally and posthumously awarded him the highest military medal of Hero of Russia, paid his respects, briefly sitting beside the coffin and speaking to Karlov’s widow.

Karlov was a Soviet-trained diplomat who worked in North and South Korea during the 1990s and 2000s and was sent to Turkey in 2013.

His name was etched into a slab of pink marble on the wall of the foreign ministry building commemorating Russian diplomats killed in the line of duty.

Proceedings moved to Moscow’s gold-domed Christ the Savior Cathedral later Thursday where the head of the Russian Orthodox Church, Patriarch Kirill, led a ceremony.

“He will go down in the history of the Fatherland,” Kirill said.

The envoy was buried later Thursday in a cemetery in a northern Moscow suburb with military honors, his coffin draped in the Russian flag.

“We must know who directed the killer’s hand,” Putin said after Karlov was assassinated.

Turkish authorities have identified the assassin as Mevlut Mert Altintas, 22, who had worked for Ankara’s riot police. He was later killed by security forces.

President Recep Tayyip Erdogan has blamed the killing on the network of US-based preacher Fethullah Gulen, something Gulen denies. The Kremlin however has said it is too early to say who stood behind the murder.

Russia has flown a team of investigators to Turkey to help with the murder investigation.