Turkish authorities have arrested 12 people on suspicion of being members of a terrorist organisation, a provincial governor said on Thursday (May 30).

The police raids were carried out in Turkey's largest city Istanbul as well as in the southern provinces of Mersin, Adana and Hatay near the Syrian border, said Adana governor Huseyin Avni Cos.

Cos said unknown chemical materials were found during the raids and sent away for investigation. He denied media reports that a small amount of the nerve agent sarin had been uncovered.

Six of those arrested were later released, Cos said, while the other six were being kept for further questioning. He did not say which organisation had been targeted in the raids.

Earlier, several Turkish newspapers had reported that 12 people from Syria's al Qaeda-linked al-Nusra Front who allegedly had been planning an attack inside Turkey and were in possession of 2 kg (4.5 pounds) of sarin, had been detained in Adana.

The group claimed responsibility for deadly bombings in Damascus and Aleppo, and its fighters have joined other Syrian rebel brigades.

Presented by Adam Justice