Russia has announced a series of economic sanctions against Turkey after the downing of a Russian jet near the Syrian border.
Turkey said the sanctions "would only damage relations", after the country's Prime Minister said he was "truly saddened" by the incident.
A fighter jet which violated Turkish air space has been shot down close to the Syrian border after ignoring warnings, a Turkish military official has said.
The official said the nationality of the downed jet is unclear.
Separately, Prime Minister Ahmet Davutoglu's office said he had spoken with the chief of military staff and the foreign minister about developments on the border.
The statement did not mention the downed jet.
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.