Russian Foreign Minister Sergei Lavrov met with a leader of Turkey's Kurdish political party, who joined Moscow in criticizing Ankara for shooting down a Russian warplane last month.
The meeting December 24 with Selahattin Demirtas, co-head of the Peoples' Democratic Party, appeared designed to irk Turkey, which has waged a bloody crackdown on Kurdish rebels on the domestic front while engaging in a tit-for-tat diplomatic war with Russia over the plane's downing.
Lavrov hailed the Turkish Kurds as potential allies against the Islamic State group and told Demirtas that Russia was ready to cooperate closely with them.
But an angry Ankara saw only "treason" in the meeting, Reuters reported.
Turkish Prime Minister Ahmet Davutoglu said the Kurdish leader's support for Moscow over the warplane, which Ankara contends strayed into Turkish airspace, was "a total disgrace and treason," Reuters reported.
"Supporting Russia while it kills civilians in Syria is treason not only against this country, but also against humanity," Davutoglu said in a meeting with Turkish business leaders.