The pills had been hidden in apple crates "loaded onto a refrigerator truck" and discovered at the Al-Qaim crossing between Syria's Deir Ezzor province and western Iraq's Anbar desert region, the Iraqi border authority said.

The truck driver had been arrested, the agency added in a statement.

A border authority official told AFP on condition of anonymity that the shipment from Syria into Iraq contained captagon pills produced by several manufacturers.

Iraqi security forces have intensified narcotics operations in recent months, with several high-profile drug seizures reported.

Sharing borders with Syria, Saudi Arabia, Iran, Kuwait and other countries, Iraq has served as a major conduit for traffickers of captagon, which is primarily produced in Syria and has its largest market in Gulf Arab states.

The sale and use of drugs in Iraq has soared in recent years.

In June, Iraqi security forces said they had forced down a microlight aircraft near the Kuwaiti border headed to the emirate from Iran with one million captagon pills.

Weeks earlier, Iraqi police announced they had seized more than six million pills of the stimulant in a major drug bust.

Areas in central and southern Iraq bordering Iran have become major narcotic trafficking routes for drugs, including crystal methamphetamine.

The interior ministry's anti-drug unit in December 2021 named the neighbouring provinces of Basra and Maysan as the "leading southern provinces in terms of trafficking and consumption".