Turkish authorities have seized a large quantity of chemicals from a convoy trying to illegally enter the country from Syria, which "could be transformed into weapons", the army says.

The convoy of three vehicles refused to stop as it attempted to illegally cross the border near the southeastern town Turkish town of Reyhanli, the army said in a statement on Sunday.

Para-military police were forced to shoot out the tyres of the vehicles to stop them, and three drivers jumped out and fled in the direction of Syria.

One of them was arrested, the army said without specifying his nationality.

The haul of sulphur and another unidentified substance will be examined by a team of army specialists, the statement said.