Turkish President Tayyip Erdogan has issued a stark message to Russia, warning them not to "play with fire" in the wake of a dispute over the downing of a Russian warplane.
He said: "We very sincerely recommend to Russia not to play with fire.
"We really attach a lot of importance to our relations with Russia... We don't want these relations to suffer harm in any way."
The warning came as Turkey made claims that Russia's criticism of the shooting down of the jet near the Syrian border on Monday, and the country's subsequent threats of economic sanctions, had been "unacceptable".
Russia's government has reportedly been drawing up measures including freezing some joint investment projects and restricting food imports from Turkey after what one politician branded as the "intentional murder of our soldiers".
Turkey has shown it is willing to take on Russia after downing a Russian fighter jet.
This incident will leave the American military profoundly alarmed that the Syrian conflict is now threatening to spiral out of all control.