The Turkish military has started building a concrete wall along the border with Syria following a series of attacks, state media said Friday.

The Turkish Armed Forces (TSK) is building the three meter (10 feet) high wall in the Reyhanli district of Hatay province just across from the Syrian town of Atmeh, the official Anatolia news agency said.

Turkish prosecutors have charged 33 people suspected of involvement in a May bomb attack that left 52 dead in a small border town and that Ankara has blamed on the Syrian secret service.

Prosecutors in the southern city of Adana are seeking life sentences for the suspects, two of whom are Syrian, after charging them with "murder with the use of explosive device", the Dogan news agency reported on Wednesday.

Key opposition group the Syrian National Council on Sunday echoed Ankara's accusation that supporters of President Bashar Assad's regime were behind twin car bomb attacks in Turkey that killed dozens a day earlier.

"The Syrian National Council condemns in the strongest terms the cowardly crimes carried out by collaborators of the Syrian regime in the Turkish town of Reyhanli," said the group, an influential faction within the leading opposition National Council.

Damascus on Sunday denied accusations it was behind twin car bomb attacks that left at least 46 people dead in a Turkish town near the Syrian border, as Ankara arrested nine people in the probe.

Cranes were seen lifting debris from buildings destroyed by Saturday's blasts in Reyhanli, one of the main Turkish hubs for Syrian refugees and rebels.

Iran has condemned as a "savage terrorist crime" twin car bomb attacks which killed 43 people and injured dozens in a small Turkish town near the Syrian border, media reported on Sunday.

The state broadcaster's website quoted Deputy Foreign Minister Abbas Araqchi as saying that "confronting terrorism is the duty of all countries".