A Saudi prince has been detained at Beirut airport in Lebanon after two tons of an amphetamine drug popular with Syrian rebels was found on a private jet. Prince Abdel Mohsen Bin Walid Bin Abdulaziz and four other men were held after what was described as the biggest ever drugs bust at the city's main Rafik Hariri International Airport. They were allegedly attempting to smuggle about two tons of Captagon pills and some cocaine", a security source was quoted as saying. Captagon is a brand name for the widely used amphetamine phenethylline. Although this type of amphetamine has been prescribed in the past to treat childhood and other behavioural disorders, it is now used overwhelmingly as a stimulant in the Middle East. It has long been banned in the West. It is the drug of choice for front-line fighters on both sides in the Syrian war. It is unclear where the pills allegedly found in Beirut were ultimately to be sold, although the plane was said to be heading back to Saudi Arabia. That would fit one of the more unexpected side-effects noted of the Syrian war - the country's growing role as an exporter of illegal drugs. There have been reports that Syrian suppliers to both sides of the conflict have become so successful in manufacturing Captagon that it is now an export product, smuggled through Lebanon to a broader Middle East market. The drugs were stuffed into 40 suitcases, according to reports.