Andrei Karlov, the Russian ambassador to Turkey, was shot and killed today by 22-year old Mevlüt Mert Altintason on live camera.

The assassin yelled Allahu Akbar" and then screamed in Turkish "We die in Aleppo, you die here," a reference to the atrocities going on in Syria's largest city.

The killing comes after a week of protests in Turkey over Russian involvement in the Syrian conflict.

Altintas, an off-duty police offier, was shot dead after a 15 minute standoff with special forces. Three others were injured in the incident.

Given the United States's tricky relationship with both Turkey and Russia, this development will be a huge challenge for the current President Barack Obama and the President Elect Donald Trump.

So far neither has commented.