Syria has pledged to fight drug smuggling in talks with its Arab neighbours, but the stimulant keeps moving across the region.

Captagon is a highly addictive amphetamine-type stimulant whose trade has helped provide a financial lifeline to Syrian President Bashar al-Assad’s government during the country’s long-running war, according to experts. The government denies any organised involvement in the trade.

The Iraqi interior ministry said in a Facebook post on Wednesday that the tablets were seized in a raid at a school that was being renovated in the city of Ramadi in Al Anbar province.

It added that police also confiscated 1kg (2.2 pounds) of cannabis resin. Efforts were being made to arrest those responsible, it continued, without offering further details.

Iraq has long been a transit country for Captagon, the brand name of a psychoactive medicine produced in the 1960s by a German company as a treatment for attention deficit disorder and narcolepsy and as a central nervous system stimulant.

Syria was welcomed back into the Arab League in May amid a flurry of regional diplomatic activity that accelerated after Iran and Saudi Arabia agreed to restore diplomatic relations in a China-brokered deal in March.

As part of talks to end its isolation, the al-Assad government agreed to tackle drug trafficking across its borders with neighbours Jordan and Iraq, which have borne the brunt of the Captagon exports.

But countries across the region have continued to be afflicted by the effects of the drug trade, which is believed to be worth billions of dollars a year.

On Tuesday, police in Lebanon said they had seized an estimated 450,000 Captagon pills in a raid on a warehouse near Beirut International Airport after receiving a tip that the shipment was to be sent to the Democratic Republic of the Congo and then to an unnamed Gulf country.

Last week, Oman announced one of its largest seizures, which amounted to 6 million Captagon pills.

Police in the sultanate said they carried out an operation on an “international network that was smuggling large quantities of drugs and psychotropic substances” with the help of Saudi Arabia, another country hugely affected by the Captagon trade.

In March, Iraqi authorities had announced the seizure of 3 million Captagon pills at the al-Qaim border crossing with Syria amid intensified narcotic operations to counter the spread of the substance.

In the same month, the United States, European Union and Britain imposed sanctions on a list of people with ties to al-Assad’s government, including two of his cousins, for involvement in the drug trade.

A BBC investigation published on Wednesday said it found evidence indicating the involvement of other senior Syrian officials in addition to those who have already been blacklisted.