ANKARA - Turkish Foreign Minister Mevlut Cavusoglu told his US counterpart John Kerry on the phone call Tuesday that Fetullah Terrorist Organization (FETO) was behind Russian envoy's assassination, local media reported.

During the phone conversation, Cavusoglu briefed Kerry on Russian Ambassador Andrey Karlov's murder, who was shot dead on Monday evening, state-run Anadolu Agency reported.

Kerry offered condolences to Cavusoglu and expressed sorrow about the incident.

The two top diplomats also discussed the trilateral meeting that took place Tuesday in Moscow between Russian, Iranian and Turkish foreign ministers.

The Russian ambassador was killed during a speech at an exhibition in Ankara on Monday evening by a gunman dressed as a guard.

Late Tuesday, Turkish Justice Minister Bekir Bozdag said that it is a great disrespect and defamation for the Turkish police to be involved as the perpetrator of Russian envoy's assassination.

"The connections behind this attack will also come to light," Bozdag said in a speech at the Turkish Parliament.

He vowed that "the investigations will reveal all the ties of the attacker."

The US-based cleric Fetullah Gulen is accused by Turkish government of conducting the July 15 failed coup attempt.