In the latest salvo of Iran's routine slaughter of narcotics offenders, some 100 prisoners jailed together for drug crimes in Iran have been informed of their impending execution.

Mahmood Moghaddam, director of the Norway-based Iran Human Rights group, revealed on Friday that sources inside and outside Ghezel Hessar prison, including a prosecutor attached to Iran's Islamic Revolutionary Court, confirmed that the inmates were told that the country's Supreme Court had upheld their sentences, and that they should prepare to be put to death.

The prospect of this mass execution for drug crimes comes just months after the United Nations Office on Drugs and Crime (UNODC) inked a new $20 million deal with Iran to assist in its counter-narcotic efforts. Advocates against the excesses of the drug war have pilloried the UN for its dealings with Iran, which kills hundreds of people every year, including foreign nationals, over drug-related charges. Iran Human Rights estimates that more than 1,800 people were executed for drug crimes in Iran between 2010 and 2014, most without due process or access to proper legal representation.

Moghaddam said that last year the number of executions for such crimes increased considerably, surpassing 600. He estimates that more than half of government executions, and in recent years as much as 70 percent, involve some connection to drugs. On a per capita basis, Iran executes more people than any other country in the world.

This February, Iranian authorities halted such killings in the weeks surrounding parliamentary elections — a common practice, and one that suggests the arbitrary ordering of executions is largely political and not aimed at actually curtailing drug trafficking or use in Iran. That perception is reinforced by Iran's progressive but apparently contradictory practice of offering some drug users access to harm-reduction methods.

Iran's location next to Afghanistan makes it a major drug trafficking conduit, and addiction within the Islamic Republic has spiked over recent years. Officials last year acknowledged that more than 2.2 million people in the country of 80 million are addicted to hard drugs like heroin and methamphetamine, with more than a million of them in some sort of treatment program.

"Iranian authorities have admitted several times that the executions do not reduce drug crimes," said Moghaddam. "The judiciary says that the drug problem has actually been increasing. So the question is why they keep on executing these people. I don't have a good answer for that."

Last week, Shahindokht Molaverdi, Iran's vice-president for woman and family affairs, raised alarm both inside and outside Iran when she informed journalists that the entire adult male population of an unidentified village in Baluchestan province had been executed for supposed ties to drug trafficking. Her comments, given to the semi-official news agency Mehr, could not be confirmed, and she has come under pressure domestically to walk back the controversial disclosure.

Such wide-scale bloodletting has increased revulsion at the international community's complicity. Maya Foa, head of the death penalty team at the UK-based human rights organization Reprieve, called the planned mass execution at Ghezel Hessar "the one tangible return on the UN's investment in Iranian drug raids."

"Iran's spree of drug-related hangings is based on unfair trials and force 'confessions,' and its main victims are innocent scapegoats and vulnerable people who've been exploited as drug mules," Foa said in a statement.

Iran's penchant for putting drug offenders to death hasn't dampened the UNODC's enthusiasm for the country's role in the drug fight.

"Iran takes a very active role to fight against illicit drugs," remarked Yury Fedotov, the UNODC's executive director, in 2014. "It is very impressive."

Ghezel Hessar prison, located on the outskirts of Tehran, is one of Iran's largest and most notorious correctional facilities. Moghaddam said that those who were informed of the decision to proceed with executions were located in an area devoted to drug offenders. Many of them have had no access to lawyers.

Last May, dozens of inmates with death sentences gathered in a prison yard at Ghezel Hessar and peacefully petitioned the state to commute their punishment to life in prison.

"Right after that gathering, the head of the prison said, 'We will execute all of you,'" said Moghaddam. "After that they started and every few days they executed groups of 11 to 17 people."

In addition to Iran's close cooperation with the UN over counter-narcotics operations, the country's ambassador in Vienna, Reza Najafi, has been appointed vice-chair of a prominent drug policy board based out of the Commission on Narcotic Drugs. The board is charged with guiding the drafting of a document that will be presented to member states at the General Assembly in New York during its upcoming special session on international drug policy in April.