Russian jet 'violated Turkey airspace'
A Russian jet has violated Turkey's airspace, despite several warnings, according to Turkish officials.
The Turkish foreign ministry has summoned the Russian ambassador after the alleged incident on Friday.
Officials said the plane was warned in Russian and in English before entering Turkey's airspace.
The statement accused Russia of escalating tensions, adding that Russia would be held responsible for any "dire" consequences.
In November, Turkey shot down a Russian plane which violated its airspace near Syria, sparking a crisis between the two countries.