The foreign ministers of Russia, Turkey and Iran are holding talks on the Syria crisis in Moscow, a day after the murder of Russia's ambassador to Turkey Andrei Karlov.

Russia's foreign minister Sergei Lavrov says the three countries will adopt tangible measures on Syria. He said the murder of Karlov won't hinder the battle against terrorism in Syria.

On the eve of the meeting, Karlov was shot in the back and killed as he gave a speech at an Ankara art gallery. The gunman was shot dead at the scene and identified as 22-year-old Mevlut Mert Altintas, a riot police officer.