Iraqi police recovered 250,000 captagon tablets from a school building site on Wednesday, the government said, a seizure that highlights a surge in consumption of the amphetamine-like stimulant.
The seizure was carried out in Anbar province on the border with Syria, a country considered the hub for production and trafficking of captagon which has flooded the Middle East.
Police "seized 250,000 captagon pills and one kilogram of cannabis resin from a school being renovated in the city of Ramadi", the interior ministry said on Facebook.
Efforts were being made to track down and arrest those responsible, it added, without elaborating.
Iraq has long been transit country for captagon, but officials say it is increasingly becoming a consumer market for the illicit drug.
The country's security forces have intensified narcotics operations in recent months, with several high-profile seizures reported.
In March, the authorities announced the seizure of three million captagon pills at the Al-Qaim border crossing with Syria.
Syria said at an Arab foreign ministers meeting in May that it was ready to "strengthen cooperation" with Jordan and Iraq, "affected by drug-trafficking and smuggling across the Syrian border".
The three countries also pledged to "take the necessary measures to put an end to smuggling operations".