Turkish authorities have arrested two suspects, including a police officer, in connection with the assassination of Russian Ambassador Andrei Karlov.
A court in Ankara ordered the arrest on January 19 of two suspects, police officer Sercan Baser and vendor Enes Asım Silin.
Two other suspects were ordered not to leave the city while investigations are under way.
Karlov was shot dead on December 19 at a photo exhibition in Ankara by Mevlut Altintas, an off-duty policeman who shouted "Don't forget Aleppo" and other words that seemed to refer to Russia's involvement in the Syrian civil war.
Russia and Turkey have backed opposing sides in the Syrian conflict, but their ties have improved substantially after being badly strained when Turkey shot down a Russian warplane along the Turkey-Syria border in November 2015.
They are now jointly supporting peace talks set to start on January 23 in Kazakhstan, and Russia said that they carried out joint air strikes against Islamic State (IS) targets in Syria for the first time on January 18.
