Turkey has summoned the Russian ambassador to Ankara, saying a Russian Su-34 fighter jet has violated its airspace.
In a statement, the foreign ministry said the jet had been warned in Russian and English before it entered Turkish airspace on Friday.
It called the alleged violation "a type of irresponsible behaviour" and warned it would hold Russia "fully responsible" for all "undesirable grave consequences" which may follow, Russia Today reports.
Tensions have remained high between the two countries after Turkey shot down a Russian Su-24 jet after it entered Turkish airspace in November.
In response, Vladimir Putin signed a decree imposing a number of sanctions against Turkey.
Russia has been conducting air strikes against troops fighting Syrian President Bashar al-Assad since September.
The foreign ministry said it views the violation as a clear sign Russia is seeking to escalate tensions with Turkey.
