The Russian ambassador to Ankara was seriously wounded in a gun attack at an art gallery in the Turkish capital on Monday and was taken to hospital, NTV and other broadcasters reported.
Hurriyet newspaper's English website said Ambassador Andrei Karlov was shot while making a speech and that Turkish special forces had surrounded the building. NTV said three other people were wounded.
CNN Turk television said shooting was continuing in the building.
Russia and Turkey have been involved in conflict in Syria across the border from where over two million Syrian refugees have settled. Turkey has been a staunch opponent of President Bashar al-Assad while Russia has deployed troops and its air force in support of the Syrian leader.
It was not immediately clear who carried out the attack. Islamic State militants have been active in Turkey and carried out several bomb attacks on Turkish targets
A photograph posted on twitter showed a man in a black suit holding a pistol, standing close to a podium in the gallery, its walls hung with pictures. Four people including what appeared to be the ambassador lay on the floor.
This is a developing story.