Turkish officials say the plane had violated Turkey’s airspace, and that it had been repeatedly warned to return to Syria, where Russian forces are supporting the regime of Bashar al-Assad. The Russians maintain that the plane was still in Syrian airspace when it was downed. NATO is holding an emergency meeting in Brussels to address the incident, which has the potential to exacerbate a conflict that has echoes of the Cold War-era proxy fights between the West and the Soviet Union.
Here is the video, from the Associated Press: