According to Turkish reports, Sweden has extradited a convicted member of the banned Kurdistan Workers' Party (PKK) to Turkey.
Mahmut Tat arrived in Istanbul on Friday night after being arrested by Swedish police, Turkey's official Anadolu News Agency reported.
According to private Turkish television channel NTV, shortly after his arrival at Istanbul Airport, Tat was arrested by Turkish police and brought before a court.
According to Anadolu, Tat was sentenced in Turkey to more than six years for membership of the PKK and fled to Sweden in 2015 to avoid his sentence.
However, an application for asylum was rejected.
Kurdish groups are at the center of a row over Sweden and Finland's NATO membership.
Turkey has accused Sweden in particular of being a haven for "terrorists" and has called for the extradition of several PKK members in a deal signed with Sweden and Finland in June.
Sweden and Finland decided to apply for NATO membership as a result of the Russian war of aggression in Ukraine.
However, Turkey has been blocking the two countries from joining the military alliance since May.