Istanbul (AFP) - The Turkish authorities have seized close to the Syrian border a record haul of almost 11 million pills of the synthetic stimulant drug captagon which is believed to play a crucial part in Syria's civil war, reports said Friday.

Anti-narcotics police confiscated over 10.9 million pills weighing almost two tonnes in two separate raids in the Hatay region on the border with Syria this week, the official Anatolia news agency and Hurriyet daily quoted the interior ministry as saying.

Captagon, based on the amphetamine phenethylline (also spelt Fenethylline), a synthetic stimulant, is a hugely popular drug in the Middle East and produced in Syria.

It has been repeatedly dubbed as the drug fuelling Syria's civil war since its production provides income for the warring factions and also keeps fighters awake and energised over long periods.

Large quantities of the drug are also illegally smuggled abroad, with Saudi Arabia a major market where the authorities repeatedly report seizures.

The reports said that 7.3 captagon pills were seized in one raid and were set to be shipped to Gulf countries by sea hidden in 1,300 oil filters.

Another 3.6 million pills were seized in a depot, the reports added.

One Syrian citizen and two Turkish nationals have been detained on suspicion of trying to organise the smuggling, the reports said.

Captagon is classified by the UN Office on Drugs and Crime as an "amphetamine type stimulant" and usually blends amphetamine, caffeine and other substances.

Lebanese authorities this month charged a Saudi prince and nine others with drug trafficking, after nearly two tonnes of captagon capsules and cocaine were found waiting to be loaded onto their private plane at Beirut airport.