Turkey's state-run news agency says a trial has opened against 33 people — including two Syrians — accused of involvement in two car bombs that killed 52 people near the Syrian border.

The attacks in Reyhanli town on May 11 were the deadliest in Turkey in years.

Turkey, which has backed the rebels in Syria's civil war, has accused Damascus of being behind the explosions and blamed them on a Turkish Marxist group with alleged links to Syria's intelligence agency.

Anadolu Agency says Monday's trial in the city of Adana, southern Turkey, involves 19 suspects charged with homicide and attempting to "quash the unity of the state," and 14 with membership in a terror organization or aiding terrorists.

Reyhanli is a main border hub for Syrian refugees and rebels.