Iran has executed nine convicted drug traffickers at a Tehran prison.

Seven of the men were hanged in connection with the confiscation of 500 kilograms of methamphetamine from a cargo ship bound for Southeast Asia.

Iranian media did not say when that seizure was made.

The other two men were hanged after being convicted of trafficking another 420 kilograms of the same drug.

Together with China, Saudi Arabia, and the United States, Iran is one of the world's leading practitioners of the death penalty.

Amnesty International reported that Iran executed at least 360 people in 2011, most of them on drug-related charges.