Flowers covered in snow are seen lying in front of the portrait of Oleg Peshkov, a Russian pilot of the downed SU-24 jet, in Lipetsk, Russia, December 2, 2015. REUTERS/Maxim Zmeyev/File Photo

ISTANBUL (Reuters) - A man suspected of killing a Russian air force pilot after his plane was shot down by a Turkish jet near the Syrian border last November is being prosecuted, a Turkish official said on Monday.

Alparslan Celik, who was fighting with a Turkish-backed Turkmen brigade opposing government forces in northern Syria at the time, was detained at the end of March in the Aegean coastal city of Izmir on unrelated charges, but a court decided in May there was insufficient evidence against him.

Celik’s prosecution was long demanded by Moscow. The Kremlin said earlier that Turkish President Tayyip Erdogan had apologised in a letter to Russian leader Vladimir Putin over the downing of the jet.