Two Chechens were buried on Monday after they were shot dead in İstanbul last week, an advocacy group said.
Turkish police launched an investigation to find who was behind the killing, media reports said, after an İstanbul-based advocacy group blamed Russian special services for the shooting.
Hundreds of people gathered at a mosque on Sunday for the funerals of the three men, who were gunned down in broad daylight on Friday on a suburban street in İstanbul's Zeytinburnu district.
"All police divisions have been put on alert to solve the murders", Turkish media said on Monday.
The three were shot dead in 22 seconds by 11 bullets fired from a pistol fitted with a silencer, it added. İstanbul police declined comment on the case.
One of the three dead Chechens, Berg-Khazh Musayev was a close associate of Caucasus Emirate leader Dokku Umarov.
Imkander, a Caucasus support association in İstanbul, pointed the finger at Russian intelligence.
"Russian intelligence, which previously brutally killed... Chechen commanders in Turkey in the same way, has added another link to the massacres with the murders carried out in the middle of İstanbul", its head Murat Ozer said in a statement.
Ozer was referring to the 2009 killing of three former Chechen rebel commanders in İstanbul.