Key Points

1.  Turkey says its forces have shot down a plane on the border with Syria
2.  Russia says an Su-24 crashed on Syrian territory after being hit by fire from the ground
3.  Turkey says the plane violated its airspace – an accusation Russia denies
4.  President Vladimir Putin calls it 'a stab in the back by the accomplices of terrorists'
5.  Turkey is a member of the Nato alliance, which has said it is ready to defend Turkey if Russia violated its airspace