A Syrian passenger plane forced to land in Turkey was carrying "illegal cargo", Turkey's foreign minister says.
Ahmet Davutoglu said "objectionable" materials had been confiscated from the plane before it was allowed to leave.
Turkey sent jets on Wednesday to intercept the plane which was en route from Moscow to Damascus, amid rumours it was carrying military equipment, the BBC reports.
The Airbus A320 had 35 passengers - far fewer than its 180 passenger capacity - and two crew.
Tension between Turkey and Syria has been high since five Turkish civilians were killed by mortar bombs last week.
In response, Turkey fired into Syria for the first time since the uprising against President Bashar al-Assad began in March last year.
Mr Davutoglu did not specify whether any weapons had been found in an hours-long search of the plane.
"There is illegal cargo on the plane that should have been reported," he told the Anatolia news agency.
But unconfirmed reports in Turkish media said the confiscated cargo included boxes of military communication equipment.
The foreign minister said the authorities would continue to investigate Syrian passenger planes flying over Turkish air space. Turkey imposed an arms embargo on Syria last September.
Meanwhile, Russia is demanding an explanation from Turkey after the interception of the plane which had Russians on board.