Iran executed 10 drug traffickers in a prison in Tehran on Wednesday, a statement on the website of the prosecutor's office said.
The men sent to the gallows were convicted of trafficking "hundreds of kilos" (pounds) of narcotics, the statement said.
Iran, where murder, rape, armed robbery, drug trafficking and adultery are punishable by death, is among countries with the highest annual record of executions in the world, along with China, Saudi Arabia and the United States.
Two weeks ago, an announcement by Iran that it had hanged 10 convicted drug traffickers prompted expressions of concern from the United Nations and the European Union.
EU foreign policy chief Catherine Ashton said she was "appalled" by the executions while the UN special rapporteur on human rights in Iran, Ahmed Shaheed, said he was "shocked."
Shaheed said at the time more than 300 people had been recorded executed in the first eight months of the year but the figure was probably much higher as Iran was restricting information on the number of people hanged.
He reported 670 executions in 2011 in Iran, which has the world's highest per capita use of the death penalty.
London-based human rights watchdog Amnesty International has repeatedly called on Iran not to execute people convicted of drug trafficking, saying the sentence is excessive.
Three-quarters of executions in Iran involve drug traffickers netted in the Islamic republic's severe anti-drug laws.
Amnesty reported on October 9 that 344 people had been executed since the beginning of the year in Iran, most of them traffickers. In 2011 it said that Iran had carried out at least 360 executions, three-quarters stemming from drug-related cases.
Iran's geographical location along an important transit route for narcotics destined for Europe and the Middle East makes it victim to a severe drug problem.
Around two million people, out of a population of 75 million, are drug addicts, 400,000 of them heroin users, according to official estimates.
Some 3,656 deaths related to drug use were recorded during the last Iranian year (March 2011 to March 2012), according to official figures from the health ministry.