Iraq has seized 250,000 Captagon pills being stored in a school in Anbar province, close to the Syrian border, authorities said on Wednesday.
Captagon is one of the Middle East's most used and addictive narcotics leading to a crackdown by officials in the Gulf. Governments are battling against increasingly innovative methods of smuggling, including in the stomachs of sheep, fake fruit and tyres.
A kilogram of cannabis was also found during the raid on a school undergoing renovations in the city of Ramadi, the interior ministry said.
It is unclear if there have been any arrests over the drugs bust, however, officials said those responsible would be tracked down.
Iraq has been a transit hub for illegal drugs for years, widely considered to be coming from Syria, which has become a production house for the amphetamine-like stimulant.
Captagon has become a vital source of funding for the Assad regime amid strict sanctions over the state's civil war.
Lebanese authorities said on Tuesday they had seized around 450,000 Captagon tablets near Beirut International Airport.
US bill targets Syrian regime-linked Captagon drug trade
Police said they believe the shipment was supposed to be sent to the Democratic Republic of the Congo and then to the region.
Last week, Oman police arrested an international drug smuggling network and seized more than six million Captagon pills.
The network was monitored and caught in co-operation with Saudi authorities, Oman police said.
They were found in warehouses ready for shipment.
The drug was created in 1961 as an alternative to amphetamines and methamphetamines. It was used to treat attention deficit hyperactivity disorder and, less commonly, depression.
It was discontinued but an illicit version of the drug continued to be produced in eastern Europe and later in the Arab region, becoming prominent in the conflict that erupted in Syria following anti-government protests in 2011.
