TEHRAN, IRAN — Iran has hanged nine convicted drug traffickers in recent days, state media reported Tuesday, as it keeps up one of the world’s highest rates of execution.

Three were hanged at a prison in the northwestern province of Ardabil on charges of “buying and transporting heroin and opium,” the official IRNA news agency said.

The other six were executed separately on charges of trafficking “methamphetamine, heroin and cannabis,” it added.

Iran lies on a major opium-smuggling route between Afghanistan and Europe and has one of the world’s highest rates of domestic opiate use.

Figures cited by the U.N. Office on Drugs and Crime in 2021 suggest 2.8 million people have a drug problem in Iran.

Iranian authorities have launched multiple campaigns to fight drug abuse and trafficking, and regularly announce large seizures of opiates smuggled from neighboring Afghanistan.

In June, Amnesty International reported that Iranian authorities had executed at least 173 people convicted of drug-related offences during the first five months of 2023.

The figure made up around two-thirds of all executions in Iran during that period, it added.

Iran says executions are carried out only after exhaustive legal proceedings and are a necessary deterrent against drug trafficking.

It executes more people per year than any other nation except China, according to Amnesty.

The Norway-based Iran Human Rights group said in November that the Islamic Republic had executed more than 700 people in 2023, the highest figure in eight years.